Unit 1 - Multiplication

Why Multiplication?
If you routinely pick up your calculator to do multiplication basic facts (problems like 8 X 7) this could be contributing to the difficulties you are having with fractions.  You might say, "Isn't that what they invented calculators for?"  It is true that the calculator is a great tool, but if you use it to do basic fact problems like 8 X 7, your brain is much less likely to recognize that 7 is a factor (a number that divides into another number without a remainder) of 56. 
This in turn causes problems when you need to simplify fractions like 56/63, because you are much less likely to know that 56 and 63 are both divisible (can be divided by without a remainder) by 7.

Having solid multiplication fact recall impacts several areas of fractions and algebra.

You may think that you just can't memorize all of those facts, but you can.  Especially when you realize that there aren't that many that you don't already know.

Multiplication Facts Activity 
Practice Websites 
Once you have a good command of multiplication facts it is time to move on to some "number theory" ideas that will give you additional tools to use when working with fractions.  Remember that you don't need to be super fast at reciting your multiplication facts, but you should have fairly fluent access to them without the use of a calculator.  Even if you have to stop a second and think about what the product is for 4 X 8, doing so regularly, without picking up your calculator, will help you become more fluent.