Children generally find division harder than multiplication. This is often because the process involves multiplying to find the answer, especially with pencil and paper methods. This page, however, is aimed at rapid answering using mental methods.
Dividing by ten is the inverse of multiplying by ten. To multiply by 10 move each digit one place to the left. To divide by ten move each digit one place to the right.
Because all the numbers are multiples of 10 there is no need to introduce the decimal point at this stage.
To divide by 100 move two places to the right.
The later questions have different parts of the number sentence to complete: multiplying is the easiest way to do these.