You need to know the least common denominator (LCD) of 69 and 91 if you want to add or subtract two fractions with 69 and 91 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 69 and 91 is 6279.
Here is a math problem example where you need to know the LCD of 69 and 91 to solve:
3/69 + 2/91 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
6279/69 = 91
6279/91 = 69
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 91 = 273
2 x 69 = 138
Step 3) Put it all together to solve the problem:
273/6279 + 138/6279 = 411/6279
= 3/69 + 2/91 = 411/6279
It's that easy! Once again, the lowest common denominator (LCD) of 69 and 91 is as follows:
6279
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