You need to know the least common denominator (LCD) of 3 and 81 if you want to add or subtract two fractions with 3 and 81 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 3 and 81 is 81.
Here is a math problem example where you need to know the LCD of 3 and 81 to solve:
3/3 + 2/81 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
81/3 = 27
81/81 = 1
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 27 = 81
2 x 1 = 2
Step 3) Put it all together to solve the problem:
81/81 + 2/81 = 83/81
= 3/3 + 2/81 = 83/81
It's that easy! Once again, the lowest common denominator (LCD) of 3 and 81 is as follows:
81
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