Maths Library

Rounding and Estimating: Grade 3 math

This topic covers rounding whole numbers to powers of ten (10, 100, 1,000, etc.) and using rounded values to estimate calculations. Pupils practise identifying adjacent multiples and applying convention rules for the halfway boundary.

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What this covers

Rounding and Estimating is taught in Grade 3 (age 8 to 9) as a topic to introduce. It sits in the Number strand.

Worked example

Round 468 to the nearest 10.

  1. Identify the two surrounding multiples of 10: 460 and 470.
  2. Look at the ones digit: it is 8.
  3. Since 8 is 5 or greater, round up to 470.

Answer: 470

Difficulty scale

The sheet generator offers five difficulty settings for this topic.

  1. Rounding 2-digit numbers to the nearest 10 using a marked number line
  2. Rounding 3-digit numbers to the nearest 10 or 100
  3. Rounding 4-digit numbers to the nearest 10, 100, or 1,000
  4. Rounding large whole numbers to any given power of ten up to 100,000
  5. Estimating the answers to multi-step calculations by prior rounding

Common mistakes

  • Always rounding down when the target digit is followed by 5 instead of rounding up
  • Changing subsequent digits to non-zero values after rounding

Curriculum links

Indicative matches to Common Core State Standards. Check wording and codes against the official document.

  • 3.NBT.A.1 Round whole numbers to the nearest 10 or 100 using place value understanding.

Sample sheet and answers

Six questions at the level's usual difficulty. Open the editor to change, add or regenerate any of them.

Rounding and Estimating

Grade 3 math

Qs
6
Marks
6
NameDateScore / 6
1.
Round 55 to the nearest ten.
[1]
2.
Round 77 to the nearest ten.
[1]
3.
Round 70 to the nearest ten.
[1]
4.
Round 82 to the nearest ten.
[1]
5.
Round 84 to the nearest ten.
[1]
6.
Round 72 to the nearest ten.
[1]

Answer key

  1. 60Look at the digit to the right of the tens place; 55 rounds to 60
  2. 80Look at the digit to the right of the tens place; 77 rounds to 80
  3. 70Look at the digit to the right of the tens place; 70 rounds to 70
  4. 80Look at the digit to the right of the tens place; 82 rounds to 80
  5. 80Look at the digit to the right of the tens place; 84 rounds to 80
  6. 70Look at the digit to the right of the tens place; 72 rounds to 70