You need to know the least common denominator (LCD) of 81 and 9 if you want to add or subtract two fractions with 81 and 9 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 81 and 9 is 81.
Here is a math problem example where you need to know the LCD of 81 and 9 to solve:
3/81 + 2/9 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
81/81 = 1
81/9 = 9
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 1 = 3
2 x 9 = 18
Step 3) Put it all together to solve the problem:
3/81 + 18/81 = 21/81
= 3/81 + 2/9 = 21/81
It's that easy! Once again, the lowest common denominator (LCD) of 81 and 9 is as follows:
81
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