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? 17, 21, 26, 32, 39, ___
Show explanation
The amount added grows by 1 each time: +4, +5, +6, +7, then +8. The next number is 47.
Skill tested: Recognizing a pattern with growing differences
Question 2 of 12
Number Series Practice Question
Quantitative
What number comes next? 27, 23, 19, 15, 11, ___
Show explanation
Each number decreases by 4. The next number is 11 - 4 = 7.
Skill tested: Completing a decreasing arithmetic number pattern
Question 3 of 12
Number Series Practice Question
Quantitative
What number comes next? 3, 5, 10, 12, 17, ___
Show explanation
The pattern alternates +2, +5. After 17, add 2 to get 19.
Skill tested: Recognizing alternating number patterns
Question 4 of 12
Number Series Practice Question
Quantitative
What number comes next? 17, 15, 13, 11, 9, ___
Show explanation
Each number decreases by 2. The next number is 9 - 2 = 7.
Skill tested: Completing a decreasing arithmetic number pattern
Question 5 of 12
Number Series Practice Question
Quantitative
What number comes next? 25, 23, 21, 19, 17, ___
Show explanation
Each number decreases by 2. The next number is 17 - 2 = 15.
Skill tested: Completing a decreasing arithmetic number pattern
Question 6 of 12
Number Series Practice Question
Quantitative
What number comes next? 20, 25, 31, 38, 46, ___
Show explanation
The amount added grows by 1 each time: +5, +6, +7, +8, then +9. The next number is 55.
Skill tested: Recognizing a pattern with growing differences
Question 7 of 12
Number Series Practice Question
Quantitative
What number comes next? 11, 16, 22, 29, 37, ___
Show explanation
The amount added grows by 1 each time: +5, +6, +7, +8, then +9. The next number is 46.
Skill tested: Recognizing a pattern with growing differences
Question 8 of 12
Number Series Practice Question
Quantitative
What number comes next? 12, 24, 33, 66, 75, ___
Show explanation
The operations alternate multiply by 2 and add 9. After 75, multiply by 2 to get 150.
Skill tested: Following an alternating two-operation number rule
Question 9 of 12
Number Series Practice Question
Quantitative
What number comes next? 6, 12, 19, 27, 36, ___
Show explanation
The amount added grows by 1 each time: +6, +7, +8, +9, then +10. The next number is 46.
Skill tested: Recognizing a pattern with growing differences
Question 10 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 11 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 12 of 12
Number Series Practice Question
Quantitative
What number comes next? 7, 11, 18, 22, 29, ___
Show explanation
The pattern alternates +4, +7. After 29, add 4 to get 33.
Skill tested: Recognizing alternating number patterns
Next practice steps
Continue with Number Analogies, Number Puzzles, or Quantitative Practice.
For grade-based mixed practice, choose a grade from the Practice menu.