To add or subtract fractions with different denominators, one must find the least common denominator and convert the fractions so they have the same denominator. This allows the fractions to be combined properly. The document demonstrates converting 1/2 to 2/4 to add to 3/4, and converting 3/5 to 6/10 to subtract from 7/10. Finding the common denominator and converting the fractions allows for accurate addition and subtraction of fractions.

1. Adding & Subtracting Fractions with Different Denominations By MRA

2. 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. 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.

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.

5. 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.