3/8 - 9/20 as a fraction

Learn how to find what is 3/8 minus 9/20 in fraction form just in a few minutes. We have covered the easiest method to write 3/8 - 9/20 as a fraction and decimal.

Summary: 3/8 minus 9/20 = -3/40
Since both fractions have unequal denominators, 3/8 minus 9/20 is an unlike fractions subtraction. For subtracting unlike fractions, you have to first find the equivalent fractions for fraction 3/8 and fraction 9/20 in order to have the same denominators for both fractions. Therefore, you have to find the LCM of denominators 8 and 20. 40 is the LCM of 8 and 20. Multiplying the LCM 40 with the numerators and denominators of both fractions (3/8 x 40/40) - (9/20 x 40/40), and simplify further in order to have the common denominator. So the equivalent fraction for 3/8 is 15/40 and for 9/20 is 18/40. By simplifying this fraction subtraction 15/40 - 18/40, it becomes -3/40.

CALCULATION: 3/8 - 9/20 as a fraction
3/8 - 9/20 = (?)
3/8 - 9/20 = [(3 x 20) - (9 x 8)]/(8 x 20)
= (60 - 72)/160
= -12/160
= (4 x -3)/(4 x 40)
= -3/40
3/8 - 9/20 = -3/40
3/8 minus 9/20 as a fraction is -3/40.

where
3/8 is a proper fraction as a minuend,
9/20 is a proper fraction as a subtrahend,
-3/40 is the difference between 3/8 and 9/20.

---

3/8 minus 9/20 as a decimal
3/8 - 9/20 = -3/40
-3/40 = -0.075
(3/8) - (9/20) as a decimal is -0.075

where
-0.075 is the difference between 3/8 and 9/20.

The below workout with step by step calculation shows how to find what is the difference between two fractions by subtracting a fraction 9/20 from 3/8. For different, unequal or unlike denominators, use any one of the following methods to find the equivalent fraction for 3/8 minus 9/20.
1. LCM method
2. Cross multiplication method.

(3/8) - (9/20) using LCM Method:
What is 3/8 minus 9/20 as a fraction?

step 1 Observe the input parameters and what to be found:
Input:
Fraction A: 3/8
Fraction B: 9/20

What to be found?
(3/8) - (9/20) = ?
Find what's the difference between 3/8 and 9/20.

step 2 Compare the denominators of fractions 3/8 and 9/20 to identify whether it is a like or unlike fraction subtraction. Since the denominators of given fractions 3/8 and 9/20 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 3/8 and 9/20:
The LCM of 8 and 20 is 40.

step 4 Write the fractions 3/8 and 9/20 in the subtraction expression form and multiply LCM with all the numerators and denominators of both fractions.
= 3/8 - 9/20
= [(3 x 40)/(8 x 40)] - [(9 x 40)/(20 x 40)]

step 5 Simplify the expression to have common denominator:
= 15/40 - 18/40

step 6 Take the common values out and rewrite the above expression like the below:
= 1/40 x (15/1 - 18/1)
= 1/40 x (15 - 18)

step 7Simplify the above expression further:
= 1/40 x -3
= -3/40
3/8 - 9/20 = -3/40

Hence,
3/8 minus 9/20 as a fraction is -3/40.

---

3/8 - 9/20 using Cross Multiplication Method:
step 1 Observe the input parameters and what to be found:
Input:
Fraction A: 3/8
Fraction B: 9/20

What to be found?
(3/8)-(9/20) = ?
Find what's the difference between 3/8 and 9/20.

step 2 Find the product of numerator of Fraction A and denominator of Fraction B (3 x 20), find the product of numerator of Fraction B and denominator of Fraction A (9 x 8), and find the product of both denominators of Fraction A and Fraction B (8 x 20) and rewrite the equation as like the below:
= (3 x 20) - (9 x 8)/(8 x 20)

step 3 Simplify and rewrite the fraction:
= (60 - 72)/160
= -12/160
= -3/40
3/8 - 9/20 = -3/40

Hence,
3/8 minus 9/20 in fraction is -3/40