If two fractions have the same denominators, we can easily perform the addition or subtraction. For addition, simply add the numbers on top. The denominator remains the same.
To subtract, we subtract the second number from the first. The denominator remains the same.
If the fractions differ in their denominators, we multiply the top and bottom by appropriate numbers to make them equal, before we add or subtract.
Then we convert as , multiplying the top and bottom by .
Which simplifies to or
We convert and as and
Or and . Then we do the subtraction:
We should first express the given fractions with the same denominator. To do this, we need what we call the least common multiple of the numbers and .
The lease common multiple (LCM)
First express the numbers and in their prime factorisation.
8=2\times 2\times 2
To find the LCM, choose the smallest multiple common to the numbers. Here this is
So, we can rewrite the fractions ,and with the denominator .
Find , giving your answer in its simplest form.
So is the LCM
is the prime, so that 29/80 is the simplified form.