5th grade
posted by brianna .
can you explain to me how to add and subtract fractions like 2/5 + 5/12 or 7/12  8/9? i'm having trouble on this and i'm always forgetting how to do it.

You need to find the common denominator.
2/5 + 1/12
What is the smallest number that can be divided by both 5 and 12? It helps to look at the multiples of the larger number. Then find which of those number is divisible by 5.
12, 24, 36, 48, 60, 72??
Did you get 60? Good, because 60 is the common denominator.
2/5 = ?/60
Now, to find the numerator. Divide 60 by 5. That's 12, right? Next multiply 12 * 2
2/5 = 24/60
5/12 = 25/60
24/60 + 25/60 = 49/60
Please read the above carefully and then try to solve the second probem.
7/12  8/9
Respond to this Question
Similar Questions

math
8 2/3  5 1/3 How would you set up? Go here and scroll to 4 http://www.themathpage.com/ARITH/addfractionssubtractfractions1.htm the answer would be 3 1/3 
math ( subtracting fractions)
12 1/4 4 1/8 When you add or subtract fractions, you have to have the same denominator. In this problem you have to change 1/4 to 2/8. Then subtract the fraction and then subtract the whole number. Please post your answer and we'll … 
math 116
Is it always necessary to have a common denominator to add and subtract fractions? 
5th grade
How do you add fractions with different denominators? 
math
i am having to add, subtract, multiplication and division on fractions. whloe numbers with fraction. My question is that i do not know how to do fractions at all and i need some help 
5th Grade fractions
Walt has a piece of rope which is 10 1/3 feet long. He has to cut it into 4 equal pieces. How long will each piece be? 
MaTh fractions add subtract
having trouble doing these can you help? 8) 2n/5 + (n/6) 12) 3/54 + 1/54 14) 2 7/10  3 7/20 i started this one and got 2 14/20  3 7/20 then got stuck? 
Math
Shelly and Marcom are selling popcorn for their music club. Each of them received a case of popcorn to sell. Shelly has sold 7/8 of her case and Marcon has sold 5/6 of his case. Which of the following explains how to find the portion … 
5th grade Math
How do you add fractions with different denominators? 
Estimating sums and differnces of fractions
Hello! My 10 year old daughter is having trouble understanding these preparation questions from her math teacher. I know the answer but I don't know how to explain it to her.. I'm sorry if that doesn't make any sense. When I was in …