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# Can you help me with math please?

Find the sum or difference

1. 7/12 + 7/10

3. - 4/17 + 3/5

5. - 1/6 - 9/22

7. 9/20 - 3/16

9. 5/6 + - 3/10

11. - 3/10 - 5/6

### 1 Answer

- 8 years agoFavorite Answer
Since they are fractions, you should first find the (least) common denominator to each "pair" of fractions. Solutions are repeated at the bottom

(To find any common denominator, multiply the denominators, and the product should be one.)

1) The least common denominator to 7/12 + 7/10 is 60, so when you multiply the top and bottom of 7/12 by 5, it becomes 35/60. multiplying 7/10 by 6 makes it 42/60. Now that they have common denominators, you can add the (new) numerators (the denominators stay the same). This becomes 35/60 + 42/60 = 77/60.

3) It may be useful to swap the positions of the two fractions, which makes it 3/5 - 4/17. Their common denominator is 85. With common denominators, they become 51/85 - 20/85 = 31/85

5) After getting denominators of same numbers, the equation becomes -22/132 - 54/132= -76/132, which simplify's to -19/33. (when you subtract a negative number by another number, it result will be negative.

7) The common denominator of this equation is 80; multiply the top and bottom of 9/20 by 4, and multiply the top bottom of 3/16 by 5. The equation will become 36/80 - 15/80 = 21/80.

9) When you add by a negative number, it is pretty much the same as subtracting. The equation becomes 25/30 -9/30 = 16/30

11) Like question (5), it has two negative numbers. It will become -9/30 - 25/30 = -34/30

Solutions:

1) 77/60

3) 31/85

5) -19/33

7) 21/80

9) 16/30

11) -34/30

Source(s): My calculator