To write fractions in simplest form, you need to find the GCF or greatest common factor. For example, 4/12 would be written as 1/3 because 4 goes into itself once, and 4 goes into 12 exactly 3 times. You take the top number and see if it can be divided into the bottom number first, and if that doesn’t work find out the next highest number that will divide into both the top and bottom numbers the fewest times! This is called reducing, by the way. Piece of cake!