Unit 3: Fractions 3.5 – 3.6: Dividing Fractions and Mixed Numbers
Reciprocal: when you flip a fraction around (the numerator becomes the denominator and vice versa) Divisor: the number that divides into another number (the 2 nd number in a dividing equation)
There are 3 Simple Steps to Divide Fractions: Step 1. Turn the divisor (second fraction - the one you want to divide by) upside- down (this is now a reciprocal).reciprocal Step 2. Multiply the first fraction by that reciprocalMultiply Step 3. Simplify the fraction (if needed) Simplify
Example 1 Divide: ¾ x 5/6 Step one: Find the reciprocal of the divisor. –Flip 5/6 around. It is now 6/5. Step two: Multiply the numerators and denominators together. – 3 x 6 3 x 6 = x 5 = 2020 Step three: Simplify, if needed. –18/20 (divide top and bottom by 2) = 9/10
Example 2 Step 1. Turn the second fraction upside-down (it becomes a reciprocal): –In this case, we turn the ¼ around and we get 4/1 or just 4. Step 2. Multiply the first fraction by that reciprocal: –In this case, what is 3 x 4? Step 3. Simplify the fraction: –In this case, the fraction is already in simplest form.
Try on your own: 5/6 ÷ 2/3
When we multiply mixed numbers, always put mixed numbers into improper fraction form first, and then multiply by the reciprocal.