So for LA we had to do a grammar project! I did how to use numbers in a sentence because I wanted to know how to use them to improve my writing. Here is one rule: if you have two numbers in a row, spell out the first. That means in a sentence like: There were 12 7 year olds in the room, you would change it to: There were twelve 7 year olds in the room. It was fun presenting all of the rules then giving a little quiz to the class (which they passed!).