math homework?

Question

subtract 1/4 -3/10

Answer 1

The Least Common Denominator (LCD) is the Least Common Multiple of two or more denominators.

How to find the Least Common Denominator:

Find the Greatest Common Factor of the denominators.
Multiply the denominators together.
Divide the product of the denominators by the Greatest Common Factor.
Example: Find the LCD of 2/9 and 3/12

Determine the Greatest Common Factor of 9 and 12 which is 3
Either multiply the denominators and divide by the GCF (9*12=108, 108/3=36)
OR - Divide one of the denominators by the GCF and multiply the quotient times the other denominator (9/3=3, 3*12=36)
How to rename fractions and use the Least Common Denominator:

Divide the LCD by one denominator.
Multiply the numerator times this quotient.
Repeat the process for the other fraction(s)
Example: Add 2/9 + 3/12

LCD is 36
First fraction (2/9): 36/9 = 4, 4*2 = 8, first fraction is renamed as 8/36
Second fraction (3/12): 36/12 = 3, 3*3 = 9, second fraction is renamed as 9/36
It is possible to add or subtract fractions that have the same denominator
8/36 + 9/36 = 17/36

Answer 2

you need to find the common denominator. Multiply 1/4 by 5, you get 5/20. Multiply 3/10 by 2 and you get 6/20. Subtract the numerator, 5-6 and you get -1. So the answer is:

-1/20

Answer 3

First find a common denominator. The easiest way is to put one denominator over the other ( 4/10 ) then reduce it (divide both by 2 and get 2/5). If you then take the first denominator times the bottom number and the second one by the first number you get a common denominator of 20.

Next, Change both fractions to ones with denominators of 20. You get 5/20 and 6/20. so the answer is - 1/20.

Answer 4

1 over 20

Answer 5

1 over 20

Answer 6

1/20

Answer 7

1/20

Answer 8

you have to put you fraction on the same number!

so 1(4 would be 10(40 and 3(10 would be 12(40

so the answer is 10-12=-2(40 or 1(20

Answer 9

-1/20

Answer 10

-1/20