Subtract from larger numbers
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Subtract from larger numbers: skill guide
| Objective | Learners take 4 to 9 away from a number between 22 and 39, using ten strips to find what remains. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.2.NBT.B.5 |
| Difficulty | Developing · Mixed |
| Representation | Ten strip, Numerical equation |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners take 4 to 9 away from a number between 22 and 39, using ten strips to find what remains.
What this practice covers
Each problem shows a number from 22 to 39 as dots in ten strips, with an equation such as 34 − 6 = □. The learner takes away 4 to 9 and chooses how many remain. Some problems take away more dots than the last strip holds, so the learner also takes from a full strip of ten. After the learner answers, the dots that were taken away fade.
Standards alignment
Prepares for Common Core: CCSS.MATH.CONTENT.2.NBT.B.5 — Fluently add and subtract within 100 using strategies based on place value and properties of operations.
Who it’s for
This practice is designed for Grade 1 learners extending subtraction to numbers in the 20s and 30s. It is also useful for older learners who want a quick visual review of subtracting a one-digit number.
What to know first
- Learners should count reliably to 40, read two-digit numerals, and understand subtraction as taking away and finding what remains.
Difficulty and scaffolding
Developing · Mixed stage
Problem representations
- Ten strip
- Numerical equation
Three worked examples
- 28 − 5 = 23: take 5 of the 8 dots in the last strip. 2 full strips and 3 more dots remain.
- 34 − 6 = 28: take the 4 dots in the last strip to reach 30, then 2 more from a full strip. 28 dots remain.
- 31 − 7 = 24: take the 1 dot in the last strip, then 6 more from a full strip. 2 full strips and 4 dots remain.
Likely misconceptions
- Learners may report the number taken away instead of the number that remains, or take the smaller ones digit from the larger one, as in 32 − 6 = 34. Read the equation aloud, take dots from the last strip first and then from a full strip, and check by adding the removed part back.
Hints and explanations
- 28 − 5 = 23: take 5 of the 8 dots in the last strip. 2 full strips and 3 more dots remain.
- 34 − 6 = 28: take the 4 dots in the last strip to reach 30, then 2 more from a full strip. 28 dots remain.
- 31 − 7 = 24: take the 1 dot in the last strip, then 6 more from a full strip. 2 full strips and 4 dots remain.
What to practice next
Next, subtract a one-digit number from numbers up to 89 using numerals only, without ten strips.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Subtract from larger numbers FAQs
What is the goal of subtract from larger numbers?
The goal is to subtract a one-digit number from numbers in the 20s and 30s and find what remains. A learner should be able to explain which dots are taken away and count the full strips as tens without recounting from one.
Should this practice be timed?
No timer is required. First build accurate, understandable strategies. Speed usually improves naturally as learners recognize groups of ten, familiar facts, and repeated patterns.
What should a learner do after a mistake?
Point to the dots that are taken away, count the full strips and the dots that remain, and check by adding the two parts back together. A short explanation is more valuable than immediately repeating the same guess.
How many problems should be completed at once?
A Quick check has 5 problems and a Practice session has 15. A learner may pause when attention drops. A short, successful session with clear reasoning is more useful than rushing through a longer set.