Adding and Subtracting Unlike Fractions and Mixed Numbers Using Models

Explain how to add fractions with unlike denominators.

• Find a common denominator, convert the fractions, and then add the numerators.

• Add the numerators and denominators directly.

• Multiply the fractions together.

• Subtract the smaller fraction from the larger one.

Answer explanation

To add fractions with unlike denominators, first find a common denominator. Then, convert each fraction to an equivalent fraction with this common denominator. Finally, add the numerators and keep the common denominator.

The process of adding with mixed numbers involves:

• Converting mixed numbers to improper fractions, adding them, and converting back to mixed numbers if necessary.

• Adding the whole numbers and fractions separately without any conversion.

• Converting mixed numbers to decimals and then adding them.

• Adding only the fractional parts and ignoring the whole numbers.

Answer explanation

The correct process for adding mixed numbers is to convert them to improper fractions, perform the addition, and then convert back to mixed numbers if needed. This ensures accuracy in the calculation.

How do you subtract fractions with unlike denominators?

• Find a common denominator, convert the fractions, and then subtract the numerators.

• Subtract the numerators directly and keep the denominators the same.

• Multiply the fractions and then subtract the results.

• Add the fractions first and then subtract the sum from one.

Answer explanation

To subtract fractions with unlike denominators, first find a common denominator. Then, convert each fraction to an equivalent fraction with that common denominator. Finally, subtract the numerators while keeping the common denominator.

• A

• B

• C

• D

1/4 + 3/8 =

• 5/8

• 4/8

• 4/12

1/2 + 1/8 =

• 5/8

• 2/10

• 2/8

Simply the following fraction model.

Answer explanation

The shaded area is the top number (numerator). The total boxes in one shape is the bottom number (denominator). If the numerator and denominator are the same then the answer is 1.

• F

• G

• H

• J

1/4 + 1/2 =

• 3/4

• 2/6

• 2/4

1/4 + 2/3 =

• 11/12

• 3/7

• 3/12