You need to know the least common denominator (LCD) of 87 and 7 if you want to add or subtract two fractions with 87 and 7 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 87 and 7 is 609.
Here is a math problem example where you need to know the LCD of 87 and 7 to solve:
3/87 + 2/7 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
609/87 = 7
609/7 = 87
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 7 = 21
2 x 87 = 174
Step 3) Put it all together to solve the problem:
21/609 + 174/609 = 195/609
= 3/87 + 2/7 = 195/609
It's that easy! Once again, the lowest common denominator (LCD) of 87 and 7 is as follows:
609
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