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? 15, 20, 26, 33, 41, ___
Show explanation
The amount added grows by 1 each time: +5, +6, +7, +8, then +9. The next number is 50.
Skill tested: Recognizing a pattern with growing differences
Question 2 of 12
Number Series Practice Question
Quantitative
What number comes next? 14, 16, 19, 21, 24, ___
Show explanation
The pattern alternates +2, +3. After 24, add 2 to get 26.
Skill tested: Recognizing alternating number patterns
Question 3 of 12
Number Series Practice Question
Quantitative
What number comes next? 41, 35, 29, 23, 17, ___
Show explanation
Each number decreases by 6. The next number is 17 - 6 = 11.
Skill tested: Completing a decreasing arithmetic number pattern
Question 4 of 12
Number Series Practice Question
Quantitative
What number comes next? 44, 38, 32, 26, 20, ___
Show explanation
Each number decreases by 6. The next number is 20 - 6 = 14.
Skill tested: Completing a decreasing arithmetic number pattern
Question 5 of 12
Number Series Practice Question
Quantitative
What number comes next? 52, 58, 65, 73, 82, ___
Show explanation
The amount added grows by 1 each time: +6, +7, +8, +9, +10. After 82, add 10 to get 92.
Skill tested: Recognizing a number pattern with steadily growing differences
Question 6 of 12
Number Series Practice Question
Quantitative
What number comes next? 5, 17, 53, 161, 485, ___
Show explanation
Each number is multiplied by 3 and then 2 is added. 485 x 3 + 2 = 1457.
Skill tested: Applying a repeated two-step number rule
Question 7 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 8 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 9 of 12
Number Series Practice Question
Quantitative
What number comes next? 21, 24, 28, 31, 35, ___
Show explanation
The pattern alternates +3, +4. After 35, add 3 to get 38.
Skill tested: Recognizing alternating number differences
Question 10 of 12
Number Series Practice Question
Quantitative
What number comes next? 18, 22, 28, 32, 38, ___
Show explanation
The pattern alternates +4, +6. After 38, add 4 to get 42.
Skill tested: Recognizing alternating number patterns
Question 11 of 12
Number Series Practice Question
Quantitative
What number comes next? 3, 12, 30, 66, 138, ___
Show explanation
Each number is multiplied by 2 and then 6 is added. 138 x 2 + 6 = 282.
Skill tested: Applying a repeated two-step number rule
Question 12 of 12
Number Series Practice Question
Quantitative
What number comes next? 52, 49, 46, 43, 40, ___
Show explanation
Each number decreases by 3. The next number is 40 - 3 = 37.
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.