Numerical sums with multiples of 10
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Numerical sums with multiples of 10: skill guide
| Objective | Learners will be able to add a multiple of 10 from 20 to 90 and a number from 1 to 9, in either order, from the numerals alone. |
|---|---|
| Grade | Grade 1 |
| Standard | CCSS.MATH.CONTENT.1.NBT.C.4 |
| Difficulty | Developing · Abstract |
| Representation | Numerical equation |
| Practice format | Interactive, account-free practice with immediate feedback |
Objective
Learners will be able to add a multiple of 10 from 20 to 90 and a number from 1 to 9, in either order, from the numerals alone.
What this practice covers
Each problem shows an equation such as 30 + 5 or 5 + 30, with a blank for the total. There is no picture. The learner finds the sum and taps it from five choices. The tens number is from 20 to 90 and the other number is from 1 to 9, so sums run from 21 to 99. The tens number comes first in some problems and second in others.
Standards alignment
Supports Common Core: CCSS.MATH.CONTENT.1.NBT.C.4 — Add within 100 using place-value understanding and properties of operations.
Who it’s for
This practice is for Grade 1 learners who know that a two-digit number is made of tens and ones and are ready to add tens and ones without a picture. It also suits older learners who want a quick place-value review.
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 30 + 5, three tens and 5 ones make 35.
- For 8 + 60, six tens and 8 ones make 68. The sum is the same whichever number comes first.
- For 50 + 9, the tens digit comes from 50 and the ones digit is 9, so the sum is 59.
Likely misconceptions
- Learners may count on one by one from the tens number and lose count, or mix up which digit is the tens and which is the ones. Ask how many tens and how many ones the sum has before choosing an answer.
Hints and explanations
- For 30 + 5, three tens and 5 ones make 35.
- For 8 + 60, six tens and 8 ones make 68. The sum is the same whichever number comes first.
- For 50 + 9, the tens digit comes from 50 and the ones digit is 9, so the sum is 59.
What to practice next
Next, Add 10 to larger numbers adds 10 to two-digit numbers from 21 to 89, such as 34 + 10.
Editorial review
Reviewed by Brilliant’s curriculum team. Exercises are generated within defined difficulty ranges and checked against verified answer rules.
Numerical sums with multiples of 10 FAQs
What is the goal of numerical sums with multiples of 10?
The goal is to add tens and ones accurately from the numerals alone. A learner should be able to say how many tens and how many ones are in the sum and write it as a two-digit number.
Should this practice be timed?
No timer is required. First build accurate, understandable strategies. Speed usually improves as learners see that the tens number gives the tens digit and the other number gives the ones digit.
What should a learner do after a mistake?
After a wrong answer, the learner gets a second try. Read the equation aloud, name the tens and the ones, and put them together. 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.