Quantitative battery
CogAT Number Series, explained for parents
In Number Series, your child finds the pattern in a sequence and picks what comes next. In K–2 the sequence is shown as beads on an abacus; from 3rd grade it is a row of numbers, like 44, 41, 38, 35, 32.
Key takeaways
- In K–2 (Levels 5/6 to 8) Number Series shows amounts as beads on abacus rods, read aloud and teacher-paced, and your child picks the rod that comes next.
- From 3rd grade (Level 9) the beads become rows of written numbers that children solve on their own, with 10 minutes for the subtest.
- Patterns include going up or down by the same amount, repeating, growing steps, two-step patterns such as plus 3 then minus 1, and doubling.
- Solve by saying whether it goes up, down or both, writing the jumps between numbers, and checking the rule on every step, not just the last two.
- Number Series is not on the Screening Form; block towers, skip-counting on the stairs and bead or cereal strings are easy ways to practice patterns.
On this page
What a Number Series question looks like
A Number Series question shows amounts in order, following a rule, with the next one missing. Your child works out the rule and picks what comes next. Number Series is one of three subtests in the CogAT® Quantitative battery, along with Number Analogies and Number Puzzles. It is not on the CogAT Screening Form.
Kindergarten to 2nd grade: the bead abacus
At Levels 5/6, 7 and 8, the series is shown as beads on the rods of an abacus. Each rod holds a certain number of beads, and the rods follow a pattern. The teacher reads the directions aloud and sets the pace, and no reading is needed.
Read aloud: “The beads on the abacus follow a pattern. Which rod comes next?”
- Choice A
- Choice B
- Choice C
Show the answer
Answer: C. Each rod has 2 more beads than the one before: 2, 4, 6, 8… so the next rod has 10.
An original practice question from Thinkling, in the same format as the test. Not a real test item.
The rods hold 2, 4, 6 and 8 beads: two more each time. So the next rod needs 10. The choice with 8 beads repeats the last rod, and 9 is just “one more”, a natural guess for a child who counts by ones out of habit.
3rd grade and up: rows of numbers
From Level 9 (usually 3rd grade), the beads become written numbers. Children work on their own, and the subtest is timed at 10 minutes.
Which number comes next?
- 27Choice A
- 29Choice B
- 31Choice C
Show the answer
Answer: B. Each number is 3 less than the one before: 32 − 3 = 29.
An original practice question from Thinkling, in the same format as the test. Not a real test item.
Here the numbers go down: 44, 41, 38, 35, 32. Each step is minus 3, so the next number is 29. Writing the jumps between the numbers (−3, −3, −3, −3) makes the rule easy to see. A child who takes away 1 lands on 31, and one who takes away 5 lands on 27.
What it trains
Number Series trains pattern-finding with quantities: noticing how each step relates to the one before, describing that change, and extending it. It builds number sense, such as counting by 2s, 5s and 10s and counting backwards.
It also builds the habit of testing a rule against every step, not just the last one. These are the same ideas behind skip-counting, times tables and, later on, the patterns children meet in algebra.
How many questions there are
The table shows how many Number Series questions appear at each level of CogAT Form 7 and Form 8.
| Level | 5/6 | 7 | 8 | 9 | 10–11 |
|---|---|---|---|---|---|
| Usual grade | K | 1st | 2nd | 3rd | 4th–5th |
| Questions | 14 | 16 | 18 | 18 | 18 |
| Timing | Read aloud, teacher-paced | 10 minutes | |||
Patterns to look for
- Up or down by the same amount: 2, 4, 6, 8 (plus 2); 44, 41, 38 (minus 3).
- Repeating patterns: 1, 3, 1, 3, 1… so the next is 3.
- Growing steps: 1, 2, 4, 7, 11. The jumps are 1, 2, 3, 4, so the next jump is 5 and the next number is 16.
- Two-step patterns: 5, 8, 7, 10, 9… (plus 3, minus 1, plus 3, minus 1), so the next is 12.
- Two patterns woven together: 2, 9, 4, 9, 6, 9… Every other number counts up by 2, with 9s in between, so the next is 8.
- Doubling: 3, 6, 12, 24… so the next is 48.
Start younger children with the first two kinds, using beads or blocks, and save the others for when those feel easy.
A simple routine for solving them
- Say whether it goes up, down or both. This alone can rule out some choices.
- Find the jump between each pair. For beads, count each rod; for numbers, write the jumps above the row.
- Look for the pattern in the jumps. Are they the same every time? Getting bigger? Taking turns?
- Extend it one step and check. Does your rule work on every step, from the first to the last?
Ask your child to tell you the rule before choosing (“It goes down by 3 each time”). If they can say it, they can usually use it.
Common mistakes and how to fix them
Assuming it always goes up
Children who are used to counting up may expect every pattern to grow, so a falling series like 44, 41, 38 can catch them out. Step 1 of the routine (up, down or both?) fixes this.
Checking only the last two numbers
In 5, 8, 7, 10, 9, the last step is minus 1, but the step before was plus 3. A child who looks only at 10 → 9 might answer 8 instead of 12. Checking every jump reveals the alternating rule.
Miscounting beads
Beads on a rod are easy to miscount, especially when two rods look similar. Encourage your child to point to each bead while counting, and to count again whenever two rods are close in size.
Practice ideas for home
- Stair-step towers: build towers of 1, 3 and 5 blocks and ask your child to build the next one.
- Skip-counting on the move: count by 2s up the stairs, by 5s on fingers, by 10s with dimes.
- Bead or cereal strings: make a string that follows a pattern and let your child continue it.
- Older children: write a mystery series on the fridge each morning (50, 45, 40…) and see who solves it first.
Thinkling practices the bead-abacus format for K–2, with every question read aloud, and rows of numbers for grades 3–5. When a pattern is missed, the explanation uses pictures, voice and counting badges, and difficulty adjusts so practice stays challenging but doable. For more, see the 1st grade guide and our page on CogAT practice tests.
Frequently asked questions
What is the bead abacus on the CogAT?
For kindergarten through 2nd grade, Number Series questions show amounts as beads on the rods of an abacus instead of rows of written numbers. Each rod holds a number of beads, the rods follow a pattern, and your child picks the rod that comes next. Counting carefully and noticing how the amount changes from rod to rod are the key skills.
Is Number Series on the CogAT Screening Form?
No. The Screening Form uses three subtests: Verbal Analogies, Number Analogies and Figure Matrices. Number Series is part of the full Quantitative battery, alongside Number Analogies and Number Puzzles. Ask your school or district which form your child will take, since schools use the test in different ways.
Does my child need to know multiplication for number series?
Not to get started. Many patterns only need counting up or down by the same amount. Harder patterns, such as doubling or steps that change each time, need stronger number skills, so comfortable addition, subtraction and skip-counting help, and multiplication facts help once your child is learning them in school.
How can I practice number patterns with a kindergartner?
Use things you can touch. Build towers of 1, 2 and 3 blocks and ask for the next one. Make bead or cereal necklaces with a pattern and let your child continue it. Count by 2s while climbing stairs. A few minutes, often, beats one long session, and always let your child explain the rule in their own words.
Why does my child see the pattern but choose the wrong answer?
Often it is a counting slip, or a rule checked on only part of the row. Ask your child to say the rule out loud, then check it on every step from the start. With beads, touching each one while counting helps. With numbers, writing the jumps between them makes errors easy to spot before choosing.