You need to know the least common denominator (LCD) of 20 and 89 if you want to add or subtract two fractions with 20 and 89 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 20 and 89 is 1780.
Here is a math problem example where you need to know the LCD of 20 and 89 to solve:
3/20 + 2/89 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
1780/20 = 89
1780/89 = 20
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 89 = 267
2 x 20 = 40
Step 3) Put it all together to solve the problem:
267/1780 + 40/1780 = 307/1780
= 3/20 + 2/89 = 307/1780
It's that easy! Once again, the lowest common denominator (LCD) of 20 and 89 is as follows:
1780
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