You need to know the least common denominator (LCD) of 42 and 4 if you want to add or subtract two fractions with 42 and 4 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 42 and 4 is 84.
Here is a math problem example where you need to know the LCD of 42 and 4 to solve:
3/42 + 2/4 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
84/42 = 2
84/4 = 21
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 2 = 6
2 x 21 = 42
Step 3) Put it all together to solve the problem:
6/84 + 42/84 = 48/84
= 3/42 + 2/4 = 48/84
It's that easy! Once again, the lowest common denominator (LCD) of 42 and 4 is as follows:
84
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