Children may find the easiest way to work this out is by using the column method, where all the numbers are placed in a column, one on top of the other. It is vital that they remember that the decimal points of each number must line up. Once they’ve worked out using pencil and paper, let them check on a calculator as using decimals accurately on a calculator is an important real life skill too.
I have seen a lot of kids quickly pass off their 2’s, 5’s, and 10’s. These tables have an obvious pattern and are much easier to learn. Then there is a serious slow down as kids hit the 3’s, 4’s, and 6’s. By the time they get to the 7’s, 8’s, and 9’s they’ve decided that multiplication is way too hard, and math isn’t their thing.