Lesson 1: Division Expressions with Fractions and Whole Numbers6.NOS.1

I can…

I can divide a whole number by a unit fraction and a unit fraction by a whole number by writing the whole number over 1 and using Keep, Change, Flip.

Key words

• Division of Fractions — Finding how many groups of one fraction fit inside another amount.
• Reciprocal — A fraction turned upside down.
• Quotient — The answer when you divide.
• 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).
• Unit fraction — A fraction with 1 on top, like 1/4.

Steps

1. I want to cut a 3-foot strip of tape into 1/4-foot pieces, so I write 3 ÷ 1/4.
2. The 3 is a whole number, so I put a 1 under it. Now both numbers are fractions: 3/1 ÷ 1/4.
3. Keep, Change, Flip. I keep 3/1, I change ÷ to ×, and I flip 1/4 to 4/1. That gives 3/1 × 4/1.
4. I multiply across: 3 × 4 = 12 on top and 1 × 1 = 1 on the bottom, so 3 ÷ 1/4 = 3/1 × 4/1 = 12 pieces.

Try it

What does 5 ÷ 1/4 mean, and what is the quotient?

Check your answer

How many 1/4-size pieces fit into 5; quotient is 20

5 ÷ 1/4 means 'how many 1/4-size pieces fit into 5.' Put a 1 under the 5, then Keep, Change, Flip: 5/1 × 4/1 = 20.

Sentence starter

I know ___ because ___.

Goal: I can explain each step of Keep, Change, Flip using the words reciprocal, divisor, and quotient.