Lesson

Do you remember how to round numbers ? Give this problem a try.

Round 54 to the nearest ten.

Worked Solution

Idea summary

We can use number lines to help when rounding numbers. By putting the number in our question on a number line, we can see the closest number.

Let's see how we can estimate the answer to an addition problem by rounding the numbers first.

Choose the right answer.

143 + 33 will be in the:

A

100s

B

200s

Worked Solution

Idea summary

Once we round the numbers in our question, we can then add them together to get an estimate of our answer.

uses mental and written strategies for addition and subtraction involving two-, three-, four and five-digit numbers