5 divided by8 minus 9 divided by 20

Question

simplest form  

Answer 1

5/8 - 9/20

 

Find common denominator: 40 convert fractions by multiplying numerators by same factor used to bring each denominator to 40.

 

25/40 - 18/40 = 7/40

 

Answer 2

5/8-9/20

(100-72)/160

28/160

14/80

7/40 is the simplest form as 7 is a prime number and 40 is not a multiple of 7. 

 

Given the sum or difference of any two fractions with different denominators a/b + c/d there is a formula for adding/subtracting them. It is (ad+bc)/bd