You need to know the least common denominator (LCD) of 78 and 5 if you want to add or subtract two fractions with 78 and 5 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 78 and 5 is 390.
Here is a math problem example where you need to know the LCD of 78 and 5 to solve:
3/78 + 2/5 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
390/78 = 5
390/5 = 78
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 5 = 15
2 x 78 = 156
Step 3) Put it all together to solve the problem:
15/390 + 156/390 = 171/390
= 3/78 + 2/5 = 171/390
It's that easy! Once again, the lowest common denominator (LCD) of 78 and 5 is as follows:
390
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