Missing numbers to 100
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Missing numbers to 100: skill guide
| Objective | Learners complete forward-counting rows. |
|---|---|
| Grade | Kindergarten |
| Standard | CCSS.MATH.CONTENT.K.CC.A.1 |
| Difficulty | Foundational · Abstract |
| Representation | Number sequence |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners complete forward-counting rows.
What this practice covers
Learners complete forward-counting rows. The first ten problems visit each decade in order with one missing numeral; later rows are randomized and contain several blanks.
Standards alignment
Supports Common Core: CCSS.MATH.CONTENT.K.CC.A.1 — Count to 100 by ones and by tens.
Who it’s for
This practice is for kindergarten and Grade 1 learners who count confidently through 20 and are ready to extend the same patterns through 100. The visual structure keeps tens visible while learners work with larger numerals.
What to know first
- Learners should recognize numerals through 20, count forward one number at a time, and understand that a full ten strip represents one group of ten.
Difficulty and scaffolding
Foundational · Abstract stage
Problem representations
- Number sequence
Three worked examples
- 21, 22, __, 24 is completed with 23.
- 36, 37, 38, __, 40 is completed with 39.
- 61, __, __, 64 is completed with 62 and 63.
Likely misconceptions
- Common mistakes include writing a tens digit from a different row, such as 52 in the row from 61 to 70, or reversing the digits, such as 26 for 62. Encourage learners to name the tens first, then check the ones.
Hints and explanations
- 21, 22, __, 24 is completed with 23.
- 36, 37, 38, __, 40 is completed with 39.
- 61, __, __, 64 is completed with 62 and 63.
What to practice next
Next, Count with ten strips to 100 shows amounts from 20 to 100 as stacked strips of ten dots, and learners type how many dots there are.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Missing numbers to 100 FAQs
Why practice one row at a time?
A short row keeps attention on the repeating ones pattern and the change at each new decade. It gives learners the benefit of a hundred chart without the visual load of all one hundred squares.
Should this practice be timed?
No. Accuracy and noticing structure matter more than speed. Fluency usually develops naturally after learners repeatedly connect a numeral to its place in a sequence or to groups of ten.
Why does each row start with a number ending in 1?
Each row matches one row of a hundred chart, such as 31 to 40. The ones digit counts up from 1 to 9, and the row ends at the next ten, which is always shown. Learners can use the numbers on either side of a blank to check their answer.
What should learners practice next?
Continue with place value, counting by tens, and addition or subtraction across a decade. These activities all build on seeing a two-digit number as tens and ones.