You need to know the least common denominator (LCD) of 9 and 81 if you want to add or subtract two fractions with 9 and 81 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 9 and 81 is 81.
Here is a math problem example where you need to know the LCD of 9 and 81 to solve:
3/9 + 2/81 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
81/9 = 9
81/81 = 1
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 9 = 27
2 x 1 = 2
Step 3) Put it all together to solve the problem:
27/81 + 2/81 = 29/81
= 3/9 + 2/81 = 29/81
It's that easy! Once again, the lowest common denominator (LCD) of 9 and 81 is as follows:
81
Find Least Common Denominators
Enter another two numbers below to find the Least Common Denominator.