Add numbers across 10
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Add numbers across 10: skill guide
| Objective | Learners will be able to add two single-digit numbers with a sum from 11 to 18 from the numerals alone by making 10 first. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.1.OA.C.6 |
| Difficulty | Developing · Abstract |
| Representation | Numerical equation |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners will be able to add two single-digit numbers with a sum from 11 to 18 from the numerals alone by making 10 first.
What this practice covers
Each problem shows an equation such as 7 + 5, with a blank for the total. There is no picture. The learner finds the sum and taps it from five choices. The first number is from 4 to 9, the second is from 3 to 9, and every sum is from 11 to 18.
Standards alignment
Supports Common Core: CCSS.MATH.CONTENT.1.OA.C.6 — Add and subtract within 20 using strategies such as making ten.
Who it’s for
This practice is for Grade 1 learners who know the pairs that make 10 and are ready to add past 10 from the numerals alone. It also suits older learners who still count on by ones for these facts.
What to know first
- Learners should count reliably, read two-digit numerals, and understand addition as joining parts. Problems show numerals only.
Difficulty and scaffolding
Developing · Abstract stage
Problem representations
- Numerical equation
Three worked examples
- For 7 + 5, split 5 into 3 and 2. 7 + 3 = 10, then 10 + 2 = 12.
- For 9 + 6, 9 needs 1 to make 10, which leaves 5 from the 6. 10 + 5 = 15.
- For 4 + 9, start with the 9. It needs 1 to make 10, which leaves 3 from the 4. 10 + 3 = 13.
Likely misconceptions
- Learners may count on by ones and lose track as they pass 10, or split the second number into the wrong parts. Ask how many the first number needs to make 10, then how many are left.
Hints and explanations
- For 7 + 5, split 5 into 3 and 2. 7 + 3 = 10, then 10 + 2 = 12.
- For 9 + 6, 9 needs 1 to make 10, which leaves 5 from the 6. 10 + 5 = 15.
- For 4 + 9, start with the 9. It needs 1 to make 10, which leaves 3 from the 4. 10 + 3 = 13.
What to practice next
Next, Number pairs that make 20 asks how many more a number from 10 to 19 needs to make 20.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Add numbers across 10 FAQs
What is the goal of add numbers across 10?
The goal is to add past 10 from the numerals alone by making 10 first. A learner should be able to split one number, make 10, and add what is left.
Should this practice be timed?
No timer is required. First build accurate, understandable strategies. Speed usually improves as learners know the pairs that make 10 and use them without counting.
What should a learner do after a mistake?
After a wrong answer, the learner gets a second try. Ask how many the larger number needs to make 10, take that from the other number, and add what is left to 10. A short explanation helps more than a quick second 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 one.