Step by step
The question
Question: find the width w of a rectangle with area 48 square units and length 8.
1 Write the rule
The area of a rectangle is length times width.
So A = length × width.
2 Put the numbers in
The area is 48 and the length is 8.
So 8 × w = 48.
Careful!
The area is times, not plus.
So we divide by 8.
We do not take it away.
3 Remove the × 8
We want w by itself.
The times 8 is in the way.
To remove times 8, we divide by 8.
We do it on both sides.
Why both sides?
The = sign means both sides are the same amount.
If we change only one side, they are not the same any more.
8 divided by 8 is 1.
So just w is left.
48 divided by 8 is 6.
So the width is 6.
4 Check
Let's check: length times width, 8 times 6.
We get 48, the area.
So the width is right!
Let's look back.
First: write the rule.
Then: put the numbers in.
Then: remove the × 8.
Last: check.