Estimations are used to quickly estimate the answer of an
You look at the last digit in each number
If the last number is < 5, then round off to the nearest
If the last number is ≥ 5, then round off to the nearest 10
You can estimate products and quotients as well.
Round off the factors and multiply the factors.
Multiply the two decimal numbers.
First we multiply the two numbers without estimating this to be
able to compare the different results.
Now if we would have estimated the answer instead we would have
round off 3.5 to 4 and 7.3 to 7. This would have given us an
As we can see the answers are pretty similar, but not
Video lesson: Estimate