Division table
This is a simple exercise but worth doing. Draw a table with numbers 1, 2, 3 etc along the top and down the side. Then in the spaces write the decimal for the fraction which is the top number divided by the side number.
This is what it looks like.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
| 1 | 1 | |||||||||
| 2 | 0.5 | 1 | ||||||||
| 3 | 0.3333 | 0.6667 | 1 | |||||||
| 4 | 0.25 | 0.5 | 0.75 | 1 | ||||||
| 5 | 0.2 | 0.4 | 0.6 | 0.8 | 1 | |||||
| 6 | 0.1667 | 0.3333 | 0.5 | 0.6667 | 0.8333 | 1 | ||||
| 7 | 0.142857 | 0.285714 | 0.428571 | 0.571428 | 0.714285 | 0.857142 | 1 | |||
| 8 | 0.125 | 0.25 | 0.375 | 0.5 | 0.625 | 0.75 | 0.875 | 1 | ||
| 9 | 0.1111 | 0.2222 | 0.3333 | 0.4444 | 0.5556 | 0.6667 | 0.7778 | 0.8889 | 1 | |
| 10 | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1 |
I don't expect you to remember the sevenths but the others you should. Even the sevenths can be remembered, if you notice that the same 6 digits are always in the same order but each fraction starts with a different one.
It isn't hard, but it is important that you are just as familiar with the simple divisions as you are with your times tables. You should instantly recognise 0.6 as 3/5, and 0.35 as 7/20. It will make so many of your questions easier to do.