Question

Subtracting fractions with unlike denominators

Answer 1

`(9)/(4) - (5)/(10) = 1(3)/(4)`

Explanation:

Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal the LCD. This is basically multiplying each fraction by 1.

LCD(9/4, 5/10) = 20

`((9)/(4) * (5)/(5) ) - ((5)/(10) * (2)/(2) ) = ?`

Complete the multiplication and the equation becomes

`(45)/(20) - (10)/(20)`

The two fractions now have like denominators so you can subtract the numerators.

Then:

`(45 - 10)/(20) = (35)/(20)`

This fraction can be reduced by dividing both the numerator and denominator by the Greatest Common Factor of 35 and 20 using

GCF(35,20) = 5

`(35 / 5 )/(20 / 5) = (7)/(4)`

The fraction

`(7)/(4)`

is the same as

7 ÷ 4

Therefore:

`(9)/(4) - (5)/(10) = 1(3)/(4)`

Apply the fractions formula for subtraction, to

`(9)/(4) - (5)/(10)`

and solve

`((9 * 10)- (5* 4) )/(4 * 10)`

`= (90-20)/(40)`

`= (70)/(40)`

Reduce by dividing both the numerator and denominator by the Greatest Common Factor GCF(70,40) = 10

`(70/ 10 )/(40 / 10) = (7)/(4)`

Convert to a mixed number using

long division for 7 ÷ 4 = 1R3, so

`(7)/(4) = 1(3)/(4)`

Therefore:

`(9)/(4) - (5)/(10) = 1(3)/(4)`

Answer 2

your awnser will be 1 3/4