CogAT Number Series Practice Questions
Number Series questions ask students to identify the rule in a sequence and choose the number that should come next.
Practice original CogAT-style number series questions for quantitative reasoning.
How to use this practice page
- Read each question carefully before selecting an answer.
- Choose A, B, C, or D, then check the answer explanation.
- Look for the reasoning rule instead of guessing from the first thing you notice.
- Use the explanations to talk through the thinking process with your child or student.
Skills practiced: sequence rules, increasing and decreasing patterns, skip counting, and multi-step reasoning.
Number Series Practice
Select an answer for each question, then check your work to see the explanation.
Question 1 of 12
Number Series Practice Question
Quantitative
What number comes next? 9, 18, 27, 54, 63, ___
Show explanation
The operations alternate multiply by 2 and add 9. After 63, multiply by 2 to get 126.
Skill tested: Following an alternating two-operation number rule
Question 2 of 12
Number Series Practice Question
Quantitative
What number comes next? 19, 22, 26, 31, 37, ___
Show explanation
The amount added grows by 1 each time: +3, +4, +5, +6, then +7. The next number is 44.
Skill tested: Recognizing a pattern with growing differences
Question 3 of 12
Number Series Practice Question
Quantitative
What number comes next? 5, 13, 29, 61, 125, ___
Show explanation
Each number is multiplied by 2 and then 3 is added. 125 x 2 + 3 = 253.
Skill tested: Applying a repeated two-step number rule
Question 4 of 12
Number Series Practice Question
Quantitative
What number comes next? 6, 11, 16, 21, 26, ___
Show explanation
Each number increases by 5. The next number is 26 + 5 = 31.
Skill tested: Completing an arithmetic number pattern
Question 5 of 12
Number Series Practice Question
Quantitative
What number comes next? 8, 10, 12, 14, 16, ___
Show explanation
Each number increases by 2. The next number is 16 + 2 = 18.
Skill tested: Completing an arithmetic number pattern
Question 6 of 12
Number Series Practice Question
Quantitative
What number comes next? 52, 42, 32, 22, 12, ___
Show explanation
Each number decreases by 10. The next number is 12 - 10 = 2.
Skill tested: Completing a decreasing arithmetic number pattern
Question 7 of 12
Number Series Practice Question
Quantitative
What number comes next? 2, 4, 7, 11, 16, ___
Show explanation
The amount added grows by 1 each time: +2, +3, +4, +5, then +6. The next number is 22.
Skill tested: Recognizing a pattern with growing differences
Question 8 of 12
Number Series Practice Question
Quantitative
What number comes next? 10, 13, 17, 22, 28, ___
Show explanation
The amount added grows by 1 each time: +3, +4, +5, +6, then +7. The next number is 35.
Skill tested: Recognizing a pattern with growing differences
Question 9 of 12
Number Series Practice Question
Quantitative
What number comes next? 9, 16, 19, 26, 29, ___
Show explanation
The pattern alternates +7, +3. After 29, add 7 to get 36.
Skill tested: Recognizing alternating number patterns
Question 10 of 12
Number Series Practice Question
Quantitative
What number comes next? 9, 29, 89, 269, 809, ___
Show explanation
Each number is multiplied by 3 and then 2 is added. 809 x 3 + 2 = 2429.
Skill tested: Applying a repeated two-step number rule
Question 11 of 12
Number Series Practice Question
Quantitative
What number comes next? 7, 14, 17, 34, 37, ___
Show explanation
The operations alternate multiply by 2 and add 3. After 37, multiply by 2 to get 74.
Skill tested: Following an alternating two-operation number rule
Question 12 of 12
Number Series Practice Question
Quantitative
What number comes next? 38, 33, 28, 23, 18, ___
Show explanation
Each number decreases by 5. The next number is 18 - 5 = 13.
Skill tested: Completing a decreasing arithmetic number pattern
Next practice steps
Continue with Number Analogies, Number Puzzles, or Quantitative Practice.
For grade-based mixed practice, choose a grade from the Practice menu.