You need to know the least common denominator (LCD) of 20 and 8 if you want to add or subtract two fractions with 20 and 8 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 20 and 8 is 40.
Here is a math problem example where you need to know the LCD of 20 and 8 to solve:
3/20 + 2/8 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
40/20 = 2
40/8 = 5
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 2 = 6
2 x 5 = 10
Step 3) Put it all together to solve the problem:
6/40 + 10/40 = 16/40
= 3/20 + 2/8 = 16/40
It's that easy! Once again, the lowest common denominator (LCD) of 20 and 8 is as follows:
40
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