5/8 minus 2/5 as a fraction

The below workout with step by step calculation shows how to find what is 5/8 minus 2/5 in simplest form by using the following methods:
1. LCM method,
2. Cross multiplication method.

Problem and Workout - LCM Method:
What is 5/8 minus 2/5 as a fraction?

step 1 Observe the input parameters and what to be found:
Input:
Fraction A: 5/8
Fraction B: 2/5

What to be found?
5/8-2/5 = ?
Find what's the difference between 5/8 and 2/5.

step 2 Compare the denominators of fractions 5/8 and 2/5 to identify whether it is a like or unlike fraction subtraction. Since the denominators of given fractions 5/8 and 2/5 are not equal, it is said to be unlike fractions subtraction.

step 3For unlike fractions subtraction, find the LCM (least common multiple) of both denominators of fractions 5/8 and 2/5:
The LCM of 8 and 5 is 40.

step 4 Write the fractions 5/8 and 2/5 in the subtraction expression form and multiply LCM with all the numerators and denominators of both fractions.
=5/8-2/5
=(5 x 40)/(8 x 40)-(2 x 40)/(5 x 40)

step 5 Simplify the expression to have common denominator:
=25/40-16/40

step 6 Take the common values out and rewrite the above expression like the below:
=1/40 x (25/1-16/1)
=1/40 x (25 - 16)

step 7Simplify the above expression further:
=1/40 x 9
=9/40
5/8-2/5=9/40

Hence,
5/8 minus 2/5 equals to 9/40 in fraction.

Problem and Workout - Cross Multiplication Method
step 1 Observe the input parameters and what to be found:
Input:
Fraction A: 5/8
Fraction B: 2/5

What to be found?
5/8-2/5 = ?
Find what's the difference between 5/8 and 2/5.

step 2 Find the product of numerator of Fraction A and denominator of Fraction B (5 x 5), find the product of numerator of Fraction B and denominator of Fraction A (2 x 8), and find the product of both denominators of Fraction A and Fraction B (8 x 5) and rewrite the equation as like the below:
= (5 x 5) - (2 x 8)/(8 x 5)

step 3 Simplify and rewrite the fraction:
= (25 - 16)/40
5/8-2/5 = 9/40
Hence,
5/8 minus 2/5 = 9/40