Subtract with numerals
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Subtract with numerals: skill guide
| Objective | Learners subtract a one-digit number from a two-digit number using numerals only. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.2.NBT.B.5 |
| Difficulty | Developing · Abstract |
| Representation | Numerical equation |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners subtract a one-digit number from a two-digit number using numerals only.
What this practice covers
Each problem is a subtraction equation such as 63 − 7 = □, written with numerals only. The first number is from 21 to 89 and the number taken away is from 2 to 9. Some problems cross back past a ten, as in 63 − 7 = 56. The learner chooses how many remain by counting back or by taking away enough to reach a ten first.
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 subtracting within 100. It is also useful for older learners who want a short review of subtracting a one-digit number from a two-digit number.
What to know first
- Learners should count reliably to 100, read two-digit numerals, and understand subtraction as taking away and finding what remains.
Difficulty and scaffolding
Developing · Abstract stage
Problem representations
- Numerical equation
Three worked examples
- 47 − 3 = 44: count back 3 from 47 to 46, 45, 44.
- 62 − 5 = 57: take 2 to reach 60, then 3 more to reach 57.
- 81 − 9 = 72: take 1 to reach 80, then 8 more to reach 72.
Likely misconceptions
- Learners may report the number taken away instead of the number that remains, take the smaller ones digit from the larger one, as in 63 − 7 = 64, or forget to lower the tens digit after crossing a ten, as in 52 − 4 = 58. Read the equation aloud and check the result by adding the answer and the number taken away.
Hints and explanations
- 47 − 3 = 44: count back 3 from 47 to 46, 45, 44.
- 62 − 5 = 57: take 2 to reach 60, then 3 more to reach 57.
- 81 − 9 = 72: take 1 to reach 80, then 8 more to reach 72.
What to practice next
Next, take 10 away from two-digit numbers and see that only the tens digit changes.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Subtract with numerals FAQs
What is the goal of subtract with numerals?
The goal is to subtract a one-digit number from a two-digit number using numerals alone. A learner should be able to explain each step, such as taking away enough to reach a ten and then taking the rest.
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?
Count back again from the first number, or take away enough to reach a ten first. Then check by adding the answer and the number taken away. 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.