You need to know the least common denominator (LCD) of 3 and 78 if you want to add or subtract two fractions with 3 and 78 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 3 and 78 is 78.
Here is a math problem example where you need to know the LCD of 3 and 78 to solve:
3/3 + 2/78 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
78/3 = 26
78/78 = 1
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 26 = 78
2 x 1 = 2
Step 3) Put it all together to solve the problem:
78/78 + 2/78 = 80/78
= 3/3 + 2/78 = 80/78
It's that easy! Once again, the lowest common denominator (LCD) of 3 and 78 is as follows:
78
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