Add 3 numbers
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Add 3 numbers: skill guide
| Objective | Learners will be able to add three numbers from 1 to 7, written as numerals, with totals up to 20. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.1.OA.A.2 |
| Difficulty | Developing · Abstract |
| Representation | Numerical equation |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners will be able to add three numbers from 1 to 7, written as numerals, with totals up to 20.
What this practice covers
Each problem shows an addition equation with three numbers, such as 4 + 3 + 5, and a blank for the total. There is no picture. The learner adds the three numbers and taps the total from five choices. Each number is from 1 to 7, and totals go up to 20.
Standards alignment
Supports Common Core: CCSS.MATH.CONTENT.1.OA.A.2 — Solve addition problems that call for the sum of three whole numbers whose sum is less than or equal to 20.
Who it’s for
This practice is for Grade 1 learners who can add two numbers and are ready to add three numbers without a picture. It also suits older learners who lose track of a running total.
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 4 + 3 + 5, add 4 + 3 to get 7, then add 5 to get 12.
- For 7 + 6 + 2, add 7 + 6 to get 13, then count on 2 more to get 15.
- For 6 + 2 + 4, add 6 + 4 first to make 10, then add 2 to get 12. The numbers can be added in any order.
Likely misconceptions
- Learners may add only two of the three numbers, or lose track of the running total partway through. Have them add two numbers, say that total aloud, then add the third and check that every number was used.
Hints and explanations
- For 4 + 3 + 5, add 4 + 3 to get 7, then add 5 to get 12.
- For 7 + 6 + 2, add 7 + 6 to get 13, then count on 2 more to get 15.
- For 6 + 2 + 4, add 6 + 4 first to make 10, then add 2 to get 12. The numbers can be added in any order.
What to practice next
Next, Add 10 asks for sums such as 10 + 4 and 4 + 10, where one of the two numbers is always 10.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Add 3 numbers FAQs
What is the goal of add 3 numbers?
The goal is to add three numbers accurately from the numerals alone. A learner should be able to add two of the numbers, hold that total in mind, and then add the third.
Should this practice be timed?
No timer is required. First build accurate, understandable strategies. Speed usually improves as learners recognize doubles, pairs that make 10, and other familiar facts.
What should a learner do after a mistake?
After a wrong answer, the learner gets a second try. Read the equation again, say each number, and add them in a different order to check. 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.