You have to find there common denominator. For example, if you have 1/2 and 3/4, you would try to make the 1/2 denominator a 4. 1/2*2=2/4. Now you have the common denominator 4 on both fractions. 2/4+3/4=5/4 Do the same for subtraction
Give them a common denominator and then add or subtract. So if its 1/4 and 2/3, find a number that 4 and 3 both go into or the least common denominator, in this case 4 times 3 is 12 so 12. so then multiply the numerators that you multiplied the denominators. So you said 4 times 3. and since its 1/4 then it turns into 3/12 then same with the other one to get 8/12. now 8/12 plus 3/12 is 11/12. and there you go.
