This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (306), (2) Word form uses words ('three hundred six'—note: 'hundred' is singular, no hyphen needed here, no 'and'), (3) Expanded form shows place values added together (300 + 0 + 6). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (0 = 0), rightmost is ones (6 = 6). In this problem, expanded form 300 + 6 must be converted to standard form (noting implied 0 tens). To solve, add place values (300 + 0 + 6 = 306). Choice C is correct because adding 300 + 6 correctly equals 306, including the zero placeholder in tens. Choice D represents a specific error: concatenated instead of added (300 + 6 → 3006 instead of 306). This error typically happens when students don't understand expanded form means adding not concatenating and forget zero placeholders. To help students: Practice all three forms together—show 306 in standard, word ('three hundred six'), and expanded (300 + 0 + 6) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred six' not 'three hundred zero six'). Use place value chart: write number 306, identify each digit's place and value (3 is in hundreds place = 300, 0 is in tens = 0, 6 is in ones = 6). For expanded form, emphasize place values not digits: 'The 3 represents 300, not 3. Write 300 + 0 + 6, not 3 + 0 + 6.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 3 flats (300) + 0 rods (0) + 6 units (6) = 306, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (3006 not 306).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the number 454 must be written in words. To solve, read 454 as 'four hundred fifty-four' following word form rules (hundred singular, hyphenate 'fifty-four', no 'and'). Choice A is correct because 'four hundred fifty-four' correctly uses singular 'hundred', properly hyphenates 'fifty-four', and has no 'and'. This demonstrates accurate conversion between number forms. Choice D represents a specific error: missing hyphen ('four hundred fifty four' instead of 'four hundred fifty-four'—not following hyphenation for 21-99). This error typically happens when students don't know hyphenation rules. To help students: Practice all three forms together—show 454 in standard, word ('four hundred fifty-four'), and expanded (400 + 50 + 4) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 454, identify each digit's place and value (4 is in hundreds place = 400, 5 is in tens = 50, 4 is in ones = 4). For expanded form, emphasize place values not digits: 'The 4 represents 400, not 4. Write 400 + 50 + 4, not 4 + 5 + 4.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 4 flats (400) + 5 rods (50) + 4 units (4) = 454, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (4504 not 454).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the words 'nine hundred forty-two' must be written as a number. To solve, read 'nine hundred forty-two' and write digits 942 (9 in hundreds, 4 in tens, 2 in ones). Choice C is correct because 942 correctly places 9 in hundreds place, 4 in tens place, 2 in ones place from word form 'nine hundred forty-two'. This demonstrates accurate conversion between number forms. Choice D represents a specific error: wrong digit placement ('nine hundred forty-two' → 9402 instead of 942—put digits in wrong order). This error typically happens when students don't understand place value positions. To help students: Practice all three forms together—show 942 in standard, word ('nine hundred forty-two'), and expanded (900 + 40 + 2) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 942, identify each digit's place and value (9 is in hundreds place = 900, 4 is in tens = 40, 2 is in ones = 2). For expanded form, emphasize place values not digits: 'The 9 represents 900, not 9. Write 900 + 40 + 2, not 9 + 4 + 2.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 9 flats (900) + 4 rods (40) + 2 units (2) = 942, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (9402 not 942).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, expanded form 800 + 40 + 9 must be converted to standard form. To solve, add place values: 800 + 40 = 840, then 840 + 9 = 849, write as digits (849). Choice A is correct because adding 800 + 40 + 9 correctly equals 849. This demonstrates accurate conversion between number forms. Choice B represents a specific error: concatenating instead of adding (800 + 40 + 9 → 8049 instead of 849). This error typically happens when students don't understand expanded form means adding not concatenating. To help students: Practice all three forms together—show 849 in standard, word ('eight hundred forty-nine'), and expanded (800 + 40 + 9) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 849, identify each digit's place and value (8 is in hundreds place = 800, 4 is in tens = 40, 9 is in ones = 9). For expanded form, emphasize place values not digits: 'The 8 represents 800, not 8. Write 800 + 40 + 9, not 8 + 4 + 9.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 8 flats (800) + 4 rods (40) + 9 units (9) = 849, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (8049 not 849).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (568), (2) Word form uses words ('five hundred sixty-eight'—note: 'hundred' is singular, hyphenate 21-99 like 'sixty-eight', no 'and'), (3) Expanded form shows place values added together (500 + 60 + 8). To convert between forms, understand place value: the leftmost digit is hundreds (5 = 500), middle is tens (6 = 60), rightmost is ones (8 = 8). In this problem, the number 568 must be written in word form. To solve, say hundreds ('five hundred'), then tens-ones ('sixty-eight'), combine ('five hundred sixty-eight'). Choice B is correct because 'five hundred sixty-eight' correctly uses singular 'hundred', properly hyphenates 'sixty-eight', and has no 'and'. Choice D represents a specific error: word form structure error ('five hundred and sixty-eight' with 'and', which is incorrect). This error typically happens when students use incorrect word form structure. To help students: Practice all three forms together—show 568 in standard, word ('five hundred sixty-eight'), and expanded (500 + 60 + 8) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('five hundred eight' not 'five hundred zero eight'). Use place value chart: write number 568, identify each digit's place and value (5 is in hundreds place = 500, 6 is in tens = 60, 8 is in ones = 8). For expanded form, emphasize place values not digits: 'The 5 represents 500, not 5. Write 500 + 60 + 8, not 5 + 6 + 8.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 5 flats (500) + 6 rods (60) + 8 units (8) = 568, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (5608 not 568).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the number 731 must be written in words. To solve, read 731 as 'seven hundred thirty-one' following word form rules (hundred singular, hyphenate 'thirty-one', no 'and'). Choice A is correct because 'seven hundred thirty-one' correctly uses singular 'hundred', properly hyphenates 'thirty-one', and has no 'and'. This demonstrates accurate conversion between number forms. Choice B represents a specific error: missing hyphen ('seven hundred thirty one' instead of 'seven hundred thirty-one'—not following hyphenation for 21-99). This error typically happens when students don't know hyphenation rules. To help students: Practice all three forms together—show 731 in standard, word ('seven hundred thirty-one'), and expanded (700 + 30 + 1) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 731, identify each digit's place and value (7 is in hundreds place = 700, 3 is in tens = 30, 1 is in ones = 1). For expanded form, emphasize place values not digits: 'The 7 represents 700, not 7. Write 700 + 30 + 1, not 7 + 3 + 1.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 7 flats (700) + 3 rods (30) + 1 unit (1) = 731, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (7301 not 731).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the number 860 must be written in expanded form. To solve, break 860 into place values (800 + 60 + 0, often written as 800 + 60). Choice B is correct because 800 + 60 correctly shows place values (not digits 8 + 6 + 0). This demonstrates accurate conversion between number forms. Choice D represents a specific error: wrong expanded form (8 + 6 + 0 using digits instead of 800 + 60 using place values). This error typically happens when students confuse digits with place values. To help students: Practice all three forms together—show 860 in standard, word ('eight hundred sixty'), and expanded (800 + 60) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 860, identify each digit's place and value (8 is in hundreds place = 800, 6 is in tens = 60, 0 is in ones = 0). For expanded form, emphasize place values not digits: 'The 8 represents 800, not 8. Write 800 + 60, not 8 + 6 + 0.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 8 flats (800) + 6 rods (60) + 0 units (0) = 860, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (860 not 860, but watch for errors like 8600).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the number 305 must be written in words. To solve, read 305 as 'three hundred five' following word form rules (hundred singular, no 'and', don't mention zero tens). Choice B is correct because 'three hundred five' correctly uses singular 'hundred', has no 'and', and omits zero tens. This demonstrates accurate conversion between number forms. Choice A represents a specific error: word form structure error ('three hundred zero-five' mentioning zero, should omit it). This error typically happens when students forget zero placeholder rule. To help students: Practice all three forms together—show 305 in standard, word ('three hundred five'), and expanded (300 + 0 + 5 or 300 + 5) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 305, identify each digit's place and value (3 is in hundreds place = 300, 0 is in tens = 0, 5 is in ones = 5). For expanded form, emphasize place values not digits: 'The 3 represents 300, not 3. Write 300 + 5, not 3 + 0 + 5 if omitting zero.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 3 flats (300) + 0 rods (0) + 5 units (5) = 305, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (305 not 305, but watch for errors like 3005).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the number 472 must be written in expanded form. To solve, break 472 into place values (400 + 70 + 2). Choice A is correct because 400 + 70 + 2 correctly shows place values (not digits 4 + 7 + 2). This demonstrates accurate conversion between number forms. Choice C represents a specific error: wrong expanded form (4 + 7 + 2 using digits instead of 400 + 70 + 2 using place values). This error typically happens when students confuse digits with place values. To help students: Practice all three forms together—show 472 in standard, word ('four hundred seventy-two'), and expanded (400 + 70 + 2) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 472, identify each digit's place and value (4 is in hundreds place = 400, 7 is in tens = 70, 2 is in ones = 2). For expanded form, emphasize place values not digits: 'The 4 represents 400, not 4. Write 400 + 70 + 2, not 4 + 7 + 2.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 4 flats (400) + 7 rods (70) + 2 units (2) = 472, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (4702 not 472).

This question tests 2nd grade understanding of reading and writing three-digit numbers in different forms: standard form (digits), word form (written words), and expanded form (sum of place values) (CCSS 2.NBT.A.3: Read and write numbers to 1000 using base-ten numerals, number names, and expanded form). Three-digit numbers can be written in three forms: (1) Standard form uses digits (347), (2) Word form uses words ('three hundred forty-seven'—note: 'hundred' is singular, hyphenate 21-99 like 'forty-seven', no 'and'), (3) Expanded form shows place values added together (300 + 40 + 7). To convert between forms, understand place value: the leftmost digit is hundreds (3 = 300), middle is tens (4 = 40), rightmost is ones (7 = 7). Standard to word: Say hundreds ('three hundred'), then tens-ones ('forty-seven'), combine ('three hundred forty-seven'). Word to standard: Identify hundreds value (300), tens value (40), ones value (7), write digits in order (347). Standard to expanded: Write each digit's value (300 + 40 + 7). Expanded to standard: Add values (300 + 40 + 7 = 347). In this problem, the number 639 must be written in words. To solve, read 639 as 'six hundred thirty-nine' following word form rules (hundred singular, hyphenate thirty-nine). Choice B is correct because 'six hundred thirty-nine' correctly uses singular 'hundred', properly hyphenates 'thirty-nine', and has no 'and'. This demonstrates accurate conversion between number forms. Choice A represents a specific error: hyphenation error ('six hundred thirty nine' without hyphen, should be 'thirty-nine'). This error typically happens when students don't know hyphenation rules. To help students: Practice all three forms together—show 639 in standard, word ('six hundred thirty-nine'), and expanded (600 + 30 + 9) side-by-side. Teach word form rules explicitly: (1) 'hundred' is always singular, (2) hyphenate numbers 21-99 ('twenty-one' through 'ninety-nine'), (3) no 'and' (American English standard), (4) if tens or ones is zero, don't mention it ('three hundred five' not 'three hundred zero five'). Use place value chart: write number 639, identify each digit's place and value (6 is in hundreds place = 600, 3 is in tens = 30, 9 is in ones = 9). For expanded form, emphasize place values not digits: 'The 6 represents 600, not 6. Write 600 + 30 + 9, not 6 + 3 + 9.' Practice conversions: give number in one form, convert to others. Use manipulatives (base-ten blocks) to show 6 flats (600) + 3 rods (30) + 9 units (9) = 639, connecting concrete to written forms. Watch for: digit placement errors, missing zeros, wrong hyphenation, plural 'hundreds', adding 'and', using digits instead of values in expanded form, concatenating expanded form instead of adding (6309 not 639).