Multiplying and Dividing Fractions
Grade 8 math lesson on multiplying and dividing fractions, including multiplying across numerators and denominators and dividing by multiplying by the reciprocal. Students practice fraction multiplication and division with simplification and real-world applications.
Key Concepts
New Concept To multiply fractions we multiply the numerators to find the numerator of the product, and we multiply the denominators to find the denominator of the product. What’s next Next, you’ll see this rule visualized with area models, then learn how its inverse—division—works using reciprocals in worked examples.
Common Questions
How do you multiply fractions?
To multiply fractions, multiply the numerators together and multiply the denominators together. For example, 2/3 x 3/4 = (2x3)/(3x4) = 6/12 = 1/2. Always simplify the result to lowest terms.
How do you divide fractions?
To divide fractions, multiply the first fraction by the reciprocal of the second. The reciprocal flips the fraction: the reciprocal of 3/4 is 4/3. So 2/3 divided by 3/4 = 2/3 x 4/3 = 8/9.
What is a reciprocal?
The reciprocal of a fraction is formed by flipping the numerator and denominator. The reciprocal of 3/5 is 5/3. The reciprocal of any number x is 1/x. Any number multiplied by its reciprocal equals 1.
How do you simplify when multiplying fractions?
You can simplify before multiplying by canceling common factors between any numerator and any denominator. This is called cross-canceling and makes the multiplication easier.