In this module, you can study how to divide and multiply mixed numbers.
The video above explains how to work with mixed numbers.
When multiplying with fractions, you can often replace the multiplication sign with the word "of". For example, "1/3 x 1/3" means the same thing as "1/3 of 1/3".
3 divided by 1/4 means "how many times does 1/4 go into 3?" The answer is 12.
Practice and study
Use these search terms to find your own resources:
divide fraction and mixed number
divide fraction and mixed fraction