Assuming those are denominators of fractions you wish to add or subtract, you can use any common multiple of 4 and 14; the Lowest Common Multiple (LCM), often called the Lowest Common Denominator (LCD) especially when when referring to the denominators of fraction, provides the smallest numerators.
For 4 and 14, the LCM is 28.
The common denominator is 28.
924
What would be the ideal Common Denominator for 2 and 4?
A common denominator 24.
The LCM is 52
The common denominator is 28.
84
Any multiple of 28.
924
2. 14, 4 and 42 are all divisble by 2.
A common denominator, though not the least one, is 14*49 = 686.
The LCD of 3/8 and 1/4 is 8.
The greatest common denominator is infinite.
A common denominator, though not the least, is 168.
A common denominator, though not the least one, is 14*12 = 168.
20 and 14 are both integers. The common denominator of 20/1 and 14/1 is 1. The least common multiple is 140.
To subtract fractions, you need a common denominator. In this case, the common denominator is 7. So, 8/14 is equivalent to 4/7. Subtracting these fractions gives us 0. Hence, 4/7 minus 8/14 equals 0.