When estimating you round the numbers and then calculate in your head.
That way you quickly get an approximate result and can check your written sum.
Example: 4238 + 3891
4238 is nearly 4200, and 3891 is nearly 3900.
So calculate 4200 + 3900 = 8100.
The exact result is close to 8100.
Round to the hundred or the thousand and write in the estimate.
Example
4238 + 3891 ≈8100
6790 - 2940 ≈3900
For parents
What does this exercise practice?
Estimate results by rounding and use this to check your own calculations.
Common pitfalls
Children sometimes round in the wrong direction. Say it out loud: 4238 is closer to 4200 than to 4300.
How to practice at home
While shopping, roughly round the prices and add them up in your head, then compare with the receipt.
Related: Rounding to every place, Number Sentences with a Gap, Spot the Mistake