You need to know the least common denominator (LCD) of 18 and 4 if you want to add or subtract two fractions with 18 and 4 as denominators.
The least common denominator, also called lowest common denominator (LCD), of 18 and 4 is 36.
Here is a math problem example where you need to know the LCD of 18 and 4 to solve:
3/18 + 2/4 = ?
Step 1) Take the LCD and divide each denominator by it as follows:
36/18 = 2
36/4 = 9
Step 2) Multiply each nominator with the respective answers from Step 1:
3 x 2 = 6
2 x 9 = 18
Step 3) Put it all together to solve the problem:
6/36 + 18/36 = 24/36
= 3/18 + 2/4 = 24/36
It's that easy! Once again, the lowest common denominator (LCD) of 18 and 4 is as follows:
36
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