10% of 40 is 4, so 5% of 40 is half that, which is 2!

There are several ways to do this.
You might take ten percent of 40 which is 4 and then half of 4 is the answer.

Or you can multiply 40 times 0.05. Note that to get from a percent to a decimal you move the decimal point two places to the left.
You can multiply 4 * 5 in your head can't you? Then you just have to place...

There are several ways to do this.
You might take ten percent of 40 which is 4 and then half of 4 is the answer.

Or you can multiply 40 times 0.05. Note that to get from a percent to a decimal you move the decimal point two places to the left.
You can multiply 4 * 5 in your head can't you? Then you just have to place the decimal point correctly. It's easy if you just think about what you are doing and ask yourself if the answer you got is a reasonable one.

2

5% of 40 is 2, 5/100 X 40 = 2, 200/100 = 2