To add "like" fractions you should add the numerator. To add "related" fractions you will multiply or divide, but you have to multiply or divide both the denominator and the numerator yo get your answer.

The three skills I learned were 1, when you want to make something to its smallest form you brake it dawn to a smaller form you say can I make this any smaller. 2, When the numerator is all the same the denominator needs to have less to make it greater.