You need to know the least common denominator (LCD) of 31 and 87 if you want to add or subtract two fractions with 31 and 87 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 31 and 87 is 2697.
Here is a math problem example where you need to know the LCD of 31 and 87 to solve:
3/31 + 2/87 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
2697/31 = 87
2697/87 = 31
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 87 = 261
2 x 31 = 62
Step 3) Put it all together to solve the problem:
261/2697 + 62/2697 = 323/2697
= 3/31 + 2/87 = 323/2697
It's that easy! Once again, the lowest common denominator (LCD) of 31 and 87 is as follows:
2697
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