its simple! Here is an example: 4/8 divided by 1/2; you flip the 1/2 over so it becomes 4/8 divided by 2/1. Instead of dividing, you then multiply across. The answer is...8/8!
because when you multiply the denominators it creates a much smaller proportion.for example multiply 0.5 by 0.5, the result is 0.25in fractions it is 1/2 x 1/2, the result 1/4