This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, a runner goes 29 meters, then 34 meters more, asking how many meters the runner went in total. To solve, add the two distances (29 + 34 = 63 meters total). The answer must include units (meters). Choice A is correct because adding 29 + 34 = 63 meters, which is the total distance the runner went. The answer 63 meters correctly states the result with proper units. Choice B represents a calculation error (29 - 34 = -5, but absolute or miscalculation to 5). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Goes some then more, in total—that means combine, so add. 29 + 34.' Use visual models: draw path or number line showing distances. Practice setting up equations: identify numbers and operation, write equation (29 + 34 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 29 and 34, answer should be bigger than both; if cutting 18 from 50, answer should be less than 50). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, started with 72 meters of rope and cut off 25 meters. To solve, subtract to find remaining (72 - 25 = 47 meters remain). The answer must include units (meters). Choice A is correct because subtracting 72 - 25 = 47 meters, which is the amount of rope remaining after cutting off 25 meters. The answer 47 meters correctly states the result with proper units. Choice B represents using wrong operation (added when should subtract: 72 + 25 = 97 instead of subtracting 72 - 25 = 47). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'How many remain—that means remaining, so subtract. 72 - 25.' Use visual models: draw ribbons or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (72 - 25 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (72 - 25 = 47 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 15 and 22, answer should be bigger than both; if cutting 25 from 72, answer should be less than 72). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, Sofia has 60 centimeters of string and cuts off 24 centimeters. To solve, subtract to find remaining (60 - 24 = 36 centimeters left). The answer must include units (centimeters). Choice A is correct because subtracting 60 - 24 = 36 centimeters, which is the amount of string remaining after cutting off 24 centimeters. The answer 36 centimeters correctly states the result with proper units. Choice B represents using the wrong operation (added instead of subtracted: 60 + 24 = 84). This error typically happens when students don't identify the correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, or misunderstand what the question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Cuts off some string—that means remaining, so subtract. 60 - 24.' Use visual models: draw ribbons or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (60 - 24 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (60 - 24 = 36 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 15 and 22, answer should be bigger than both; if cutting 24 from 60, answer should be less than 60). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, started with 60 centimeters of string and cut off 23 centimeters. To solve, subtract to find remaining (60 - 23 = 37 centimeters left). The answer must include units (centimeters). Choice A is correct because subtracting 60 - 23 = 37 centimeters, which is the amount of string remaining after cutting off 23 centimeters. The answer 37 centimeters correctly states the result with proper units. Choice B represents using wrong operation (added when should subtract: 60 + 23 = 83 instead of subtracting 60 - 23 = 37). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'How much string is left—that means remaining, so subtract. 60 - 23.' Use visual models: draw ribbons or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (60 - 23 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (60 - 23 = 37 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 15 and 22, answer should be bigger than both; if cutting 23 from 60, answer should be less than 60). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, two ribbons measuring 18 inches and 27 inches are taped together. To solve, add the two lengths (18 + 27 = 45 inches total). The answer must include units (inches). Choice A is correct because adding 18 + 27 = 45 inches, which is the total combined length of both ribbons taped together. The answer 45 inches correctly states the result with proper units. Choice B represents using wrong operation (subtracted when should add: 27 - 18 = 9 instead of adding 18 + 27 = 45). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Two ribbons taped together—that means combine, so add. 18 + 27.' Use visual models: draw ribbons or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (18 + 27 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 18 and 27, answer should be bigger than both; if cutting 18 from 50, answer should be less than 50). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, Amir walks 24 feet to the library, then 16 feet more to the playground, asking how far he walked in all. To solve, add the two distances (24 + 16 = 40 feet total). The answer must include units (feet). Choice B is correct because adding 24 + 16 = 40 feet, which is the total distance Amir walked in all. The answer 40 feet correctly states the result with proper units. Choice A represents using the wrong operation (subtracted when should add: 24 - 16 = 8 instead of adding 24 + 16 = 40). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Walks to library then more to playground—in all means combine, so add. 24 + 16.' Use visual models: draw path or number line showing distances. Practice setting up equations: identify numbers and operation, write equation (24 + 16 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 24 and 16, answer should be bigger than both; if cutting 18 from 50, answer should be less than 50). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, Keisha tapes together three strips of paper: 12 inches, 15 inches, and 9 inches, asking how long the paper strip is altogether. To solve, add the three lengths (12 + 15 + 9 = 36 inches total). The answer must include units (inches). Choice B is correct because adding 12 + 15 + 9 = 36 inches, which is the total combined length of the three strips taped together. The answer 36 inches correctly states the result with proper units. Choice C represents incomplete multi-step (added first two but forgot third number: 12 + 15 - 9 or similar error leading to 24). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Three strips taped together—that means combine, so add. 12 + 15 + 9.' Use visual models: draw strips or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (12 + 15 + 9 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 12, 15, and 9, answer should be bigger than each; if cutting 18 from 50, answer should be less than 50). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, Sofia’s plant is 44 cm tall and Chen’s plant is 31 cm tall, asking how much taller Sofia’s plant is than Chen’s. To solve, subtract to find difference (44 - 31 = 13 cm taller). The answer must include units (cm). Choice B is correct because subtracting 44 - 31 = 13 cm, which shows how much taller Sofia’s plant is than Chen’s. The answer 13 cm correctly states the result with proper units. Choice C represents using only one number from problem (answered 31 instead of calculating difference). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'How much taller—that means difference, so subtract. 44 - 31.' Use visual models: draw plants or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (44 - 31 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (44 - 31, not 31 - 44). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 15 and 22, answer should be bigger than both; if finding difference between 44 and 31, answer should be less than both). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, three strips of paper measuring 12 inches, 16 inches, and 9 inches are taped together. To solve, add the three lengths (12 + 16 + 9 = 37 inches total). The answer must include units (inches). Choice B is correct because adding 12 + 16 + 9 = 37 inches, which is the total combined length of the strips together. The answer 37 inches correctly states the result with proper units. Choice C represents incomplete multi-step (added first two but forgot third number: 12 + 16 = 28 instead of 12 + 16 + 9 = 37). This error typically happens when students don't identify correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, misunderstand what question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Tapes together three strips—that means combine, so add. 12 + 16 + 9.' Use visual models: draw ribbons or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (12 + 16 + 9 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 12, 16, 9, answer should be bigger than each; if cutting 18 from 50, answer should be less than 50). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.

This question tests 2nd grade understanding of solving word problems involving addition and subtraction of lengths, including finding totals, differences, and remaining amounts (CCSS 2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units). To solve a length word problem, first identify what operation is needed. If combining lengths (taping ribbons together, adding distances walked), use addition. If finding difference (how much longer, how much taller), use subtraction (larger - smaller). If finding remaining (after cutting, after using some), use subtraction (start - used = left). Then set up the equation, calculate, and state the answer with units. Addition keywords: total, altogether, combined, in all, both, together. Subtraction keywords: how much more, how much longer/taller, difference (comparison), or left, remaining, left over (take away). In this problem, Emma tapes an 18-inch ribbon to a 27-inch ribbon to make one long ribbon, asking for the combined length altogether. To solve, add the two lengths (18 + 27 = 45 inches total). The answer must include units (inches). Choice A is correct because adding 18 + 27 = 45 inches, which is the total combined length of both ribbons taped together. The answer 45 inches correctly states the result with proper units. Choice B represents using the wrong operation (subtracted when should add: 27 - 18 = 9 instead of adding 18 + 27 = 45). This error typically happens when students don't identify the correct operation from keywords, make arithmetic mistakes, don't complete all steps, use wrong numbers, forget to include units, or misunderstand what the question is asking for. To help students: Teach keyword identification—underline keywords that indicate operation (total/altogether = add, how much more/longer/left = subtract). Model thinking aloud: 'Two ribbons taped together—that means combine, so add. 18 + 27.' Use visual models: draw ribbons or number line showing lengths. Practice setting up equations: identify numbers and operation, write equation (18 + 27 = ?), solve, state answer with units. For comparison/difference problems, emphasize: bigger number - smaller number (48 - 35, not 35 - 48). For remaining problems, emphasize: start - used = left (50 - 18 = 32 left). Use consistent problem structure: read problem, identify operation, identify numbers, write equation, calculate, answer with units. Practice checking: Does my answer make sense? (If combining 18 and 27, answer should be bigger than both; if cutting 18 from 50, answer should be less than 50). Watch for: wrong operation selected, calculation errors (especially with regrouping), using only one number, forgetting units, answering different question than asked, subtraction direction errors, incomplete multi-step problems.