Adding & Subtracting Fractions Adding & Subtracting Fractions with Different Denominationswith Different Denominations

By MRABy MRA

3/4 + 1/2

These diagrams represent 3/4 + 1/2. The denominators on these fractions are different, so I have to find the common denominator. I find the least common denominator by listing all the multiples of 2 and 4 until I find a number that they both go into.

3/4 + 2/4

The common denominator was 4. So I multiplied the denominator and the numerator of 1/2 by 2 and got 2/4. Now it is 3/4 + 2/4 which equals 5/4. I didn’t have to change 2/4 because the denominator was already 4.

7/10 – 3/5

These diagrams represent 7/10 – 3/5. The denominator in these fractions are different, so I have to find the common denominator.

7/10 – 6/10

The common denominator is 10. So I multiplied the denominator and numerator of 3/5 by 2 and got 6/10. I didn’t have to change the fraction 7/10 because the denominator was already 10. The answer is 1/10.