For the subtracting fractions, I would just make them into improper fractions (examples: 6/4, 5/3). To do that, you multiply whole number by the numerator (number on top of fraction), then add the denominator (number at the bottom), and finally, leaving the denominator as is.
Then make them have the same denominator. you might have to multiply or divide in order to match the denominators. then you may add or subtract straight across. NEVER change the denominator.
note: you might be required to make the improper fractions into mixed (ex: 4 1/2)
With multiplying, just multiply across (numerator × numerator, and denominator × denominator)