Lesson 2: Division Expressions with Fractions and Mixed Numbers6.NOS.1

I can…

I can divide a fraction by a fraction and divide with mixed numbers by multiplying by the reciprocal.

Key words

• Divide Fractions — Multiply the first fraction by the reciprocal of the second fraction.
• Dividend — The total number being divided into equal groups (the number inside the division bracket).
• Divisor — The number of equal groups you are dividing into (the number outside the division bracket).
• Reciprocal — A fraction turned upside down.
• Quotient — The answer when you divide.
• Simplify — To write a fraction with smaller numbers that names the same amount, like 2/4 = 1/2.
• Mixed number — A whole number and a fraction written together, like 2 1/2. It must be rewritten as an improper fraction before dividing.
• Improper fraction — A fraction whose numerator is greater than or equal to its denominator, like 5/2.

Steps

1. Agent Rivera has 3/4 pound and each portion is 1/8 pound. I want 3/4 ÷ 1/8.
2. Keep 3/4. Change ÷ to ×. Flip the divisor 1/8 to its reciprocal 8/1.
3. Multiply across: 3/4 × 8/1 = 24/4.
4. Simplify: 24/4 = 6. So 3/4 ÷ 1/8 = 6. She can make 6 portions.

Try it

What is 5/6 ÷ 1/12?

Check your answer

10

5/6 ÷ 1/12 = 10. Using the reciprocal, 5/6 × 12/1 = 60/6 = 10. Since 5/6 = 10/12, ten 1/12-foot pieces fit into the board.

Sentence starter

I know ___ because ___.

Goal: I can explain the steps using the words reciprocal, improper fraction, mixed number, and simplify.