Subtract with ten strips
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Subtract with ten strips: skill guide
| Objective | Learners take 4 to 9 away from a number between 11 and 19, using ten strips to find what remains. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.1.OA.C.6 |
| 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 11 and 19, using ten strips to find what remains.
What this practice covers
Each problem shows a number from 11 to 19 as dots in two ten strips, with an equation such as 15 − 7 = □. The learner takes away 4 to 9 and chooses how many remain. Some problems need dots from the full strip of ten as well as the second strip. After the learner answers, the dots that were taken away fade.
Standards alignment
Supports Common Core: CCSS.MATH.CONTENT.1.OA.C.6 — Add and subtract within 20 using strategies and relationships between addition and subtraction.
Who it’s for
This practice is designed for Grade 1 learners building fluency with subtraction within 20. It is also useful for older learners who want a quick visual review of taking away from teen numbers.
What to know first
- Learners should count reliably to 20, 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
- 17 − 4 = 13: take 4 of the 7 dots in the second strip. The full strip of 10 and 3 more dots remain.
- 13 − 5 = 8: take the 3 dots in the second strip, then 2 more from the full strip. 8 dots remain.
- 15 − 9 = 6: take 9 from the full strip, which leaves 1 dot there. That 1 and the 5 in the second strip make 6.
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 13 − 5 = 12. Read the equation aloud, take dots from the second strip first and then from the full strip, and check by adding the removed part back.
Hints and explanations
- 17 − 4 = 13: take 4 of the 7 dots in the second strip. The full strip of 10 and 3 more dots remain.
- 13 − 5 = 8: take the 3 dots in the second strip, then 2 more from the full strip. 8 dots remain.
- 15 − 9 = 6: take 9 from the full strip, which leaves 1 dot there. That 1 and the 5 in the second strip make 6.
What to practice next
Next, take 4 to 9 away from numbers in the 20s and 30s, still shown in ten strips.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Subtract with ten strips FAQs
What is the goal of subtract with ten strips?
The goal is to subtract from a teen number and find what remains. A learner should be able to explain which dots are taken away and find the rest 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 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.