You need to know the least common denominator (LCD) of 7 and 81 if you want to add or subtract two fractions with 7 and 81 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 7 and 81 is 567.
Here is a math problem example where you need to know the LCD of 7 and 81 to solve:
3/7 + 2/81 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
567/7 = 81
567/81 = 7
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 81 = 243
2 x 7 = 14
Step 3) Put it all together to solve the problem:
243/567 + 14/567 = 257/567
= 3/7 + 2/81 = 257/567
It's that easy! Once again, the lowest common denominator (LCD) of 7 and 81 is as follows:
567
Find Least Common Denominators
Enter another two numbers below to find the Least Common Denominator.