Number Pattern Rules
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ISEE Middle Level: Mathematics Achievement › Number Pattern Rules
Start at 10: 10, 15, 12, 17, 14. Next number?
11
16
18
19
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence of numbers presented follows a specific rule, and students must find the next number from the options provided. The correct choice, '19,' is found by alternating adding 5 and subtracting 3. A common distractor, such as '16,' fails because it does not follow the alternating pattern. Teaching strategies include practicing with different types of sequences and encouraging students to verbalize the rule they identify. Remind students to check their rule against each number in the sequence to ensure consistency.
Which number completes the sequence: 3, 9, 27, 81, _?
84
108
162
243
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 3, 9, 27, 81 follows a multiplication pattern where each term is multiplied by 3 to get the next term (3×3=9, 9×3=27, 27×3=81). The correct choice, 243, is obtained by multiplying 81 by 3. A common distractor, such as 162, might come from doubling 81 instead of tripling it. Teaching strategies include encouraging students to identify the relationship between consecutive terms by dividing each term by the previous one. Remind students that when they identify a pattern rule, they should verify it works for all given terms before applying it to find the missing number.
If the pattern continues, what is next: 7, 14, 28, 56, 112?
120
128
216
224
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 7, 14, 28, 56, 112 follows a pattern where each term is multiplied by 2 to get the next term (7×2=14, 14×2=28, 28×2=56, 56×2=112). The correct choice, 224, is obtained by multiplying 112 by 2. A common distractor, such as 216, might come from an incorrect calculation or applying a different rule. Teaching strategies include having students verify the pattern by checking that each term divided by the previous term equals 2. Remind students that doubling patterns are common in mathematics and to carefully perform the multiplication to avoid calculation errors.
How is the sequence 10, 7, 12, 9, 14 generated?
Subtract 3, then add 5, repeat
Subtract 3 each time
Multiply by 2, then subtract 1
Add 2 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 10, 7, 12, 9, 14 follows an alternating pattern: subtract 3 (10-3=7), then add 5 (7+5=12), subtract 3 (12-3=9), then add 5 (9+5=14). The correct choice, 'Subtract 3, then add 5, repeat,' accurately describes this alternating operation pattern. A common distractor, such as 'Add 2 each time,' fails because it doesn't account for the decreasing values at positions 2 and 4. Teaching strategies include having students track whether each step increases or decreases and by how much, creating a visual pattern of operations. Remind students that some sequences use alternating rules rather than a single consistent operation.
What is the rule for the sequence: 2, 3, 5, 8, 13?
Subtract 1 each time
Add 2 each time
Add the two previous numbers
Multiply by 2 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 2, 3, 5, 8, 13 follows the Fibonacci pattern where each term is the sum of the two previous terms (2+3=5, 3+5=8, 5+8=13). The correct choice, 'Add the two previous numbers,' accurately describes this recursive rule. A common distractor, such as 'Add 2 each time,' fails because the differences between consecutive terms are not constant (they are 1, 2, 3, 5). Teaching strategies include showing students how to check if each term equals the sum of the two preceding terms and introducing them to this famous mathematical sequence. Remind students that some patterns require looking at relationships between multiple previous terms, not just consecutive pairs.
How is the sequence 9, 11, 14, 16, 19 generated?
Subtract 2, then subtract 3, repeat
Add 3 each time
Add 2, then add 3, repeat
Multiply by 2 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 9, 11, 14, 16, 19 follows an alternating pattern where we add 2 (9+2=11), then add 3 (11+3=14), then add 2 (14+2=16), then add 3 (16+3=19). The correct choice, 'Add 2, then add 3, repeat,' accurately describes this alternating addition pattern. A common distractor, such as 'Add 3 each time,' fails because the differences alternate between 2 and 3, not a constant 3. Teaching strategies include creating a table showing the differences between consecutive terms to reveal the alternating pattern. Remind students to look for patterns in the differences when the sequence doesn't follow a simple single-operation rule.
Which rule explains the sequence: 5, 8, 11, 14, 17?
Add 5 each time
Add 3 each time
Subtract 3 each time
Multiply by 3 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 5, 8, 11, 14, 17 shows a constant difference of 3 between consecutive terms (8-5=3, 11-8=3, 14-11=3, 17-14=3). The correct choice, 'Add 3 each time,' accurately reflects the mathematical operation that defines the sequence. A common distractor, such as 'Add 5 each time,' fails because adding 5 to 5 would give 10, not 8. Teaching strategies include having students systematically find the difference between each pair of consecutive numbers and verify consistency. Remind students that arithmetic sequences with constant differences are among the most common patterns they'll encounter.
What is the rule for the sequence: 6, 10, 14, 18, 22?
Add 6 each time
Multiply by 2 each time
Subtract 4 each time
Add 4 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 6, 10, 14, 18, 22 shows that each number increases by 4 (10-6=4, 14-10=4, 18-14=4, 22-18=4). The correct choice, 'Add 4 each time,' accurately reflects the mathematical operation that defines the sequence. A common distractor, such as 'Multiply by 2 each time,' fails because multiplying 6 by 2 would give 12, not 10. Teaching strategies include having students find the difference between consecutive terms and checking their rule against every pair of numbers in the sequence. Remind students to verify their answer by applying the rule to generate the entire sequence from the first number.
What is the rule for the sequence: 4, 12, 36, 108, 324?
Multiply by 2 each time
Subtract 3 each time
Multiply by 3 each time
Add 8 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence 4, 12, 36, 108, 324 shows that each term is multiplied by 3 to get the next term (4×3=12, 12×3=36, 36×3=108, 108×3=324). The correct choice, 'Multiply by 3 each time,' accurately reflects the mathematical operation that defines the sequence. A common distractor, such as 'Multiply by 2 each time,' fails because 4×2=8, not 12. Teaching strategies include having students check the ratio between consecutive terms by dividing each term by the previous one. Remind students that multiplication patterns create sequences that grow rapidly and to verify their rule works for all given consecutive pairs.
Start at 4: 4, 9, 14, 19, 24. What is the rule?
Add 5 each time
Multiply by 2 each time
Subtract 5 each time
Add 4 each time
Explanation
This question tests middle school mathematics skills, specifically identifying rules that govern number patterns. Understanding number patterns involves recognizing the rule that consistently applies to each number in a sequence, such as addition, subtraction, multiplication, or division. In this problem, the sequence of numbers presented follows a specific rule that students must identify from the options provided. The correct choice, 'Add 5 each time,' accurately reflects the mathematical operation that defines the sequence. A common distractor, such as 'Multiply by 2 each time,' fails because it suggests a different operation than the one used in the sequence. Teaching strategies include practicing with different types of sequences and encouraging students to verbalize the rule they identify. Remind students to check their rule against each number in the sequence to ensure consistency.