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Do you UNDERSTAND?Do you know HOW?
Dividing Unit Fractions by Non-Zero Whole Numbers
Independent Practice
Guided Practice
How can you model dividing a unit fraction by a whole number?Half of a casserole is left over. Ann, Beth, and Chuck are sharing the leftovers equally. What fraction of the original casserole does each person get?Make a drawing to show 1 __ 2 .
3. Construct Arguments In the example at the top, how is dividing by 3 the same as multiplying by 1 __
3 ?
4. Reasonableness When you divide a unit fraction by a whole number, will the quotient be greater than or less than the unit fraction?
Use the picture below to find each quotient.
1. 1 __ 4 4 2
2. 1 __ 4 4 4
Shade 1 __ 3 on a number line and divide 1 __ 3 into 4 equal parts.
Each part is 1 __ 12
.
Check with multiplication: 1 __ 12
3 4 5 4 __ 12
5 1 __ 3
Use a number line to find 1 __ 3 4 4.Other Examples:
Leveled Practice In 5–10, find the quotient.
5. 1 __ 2 4 5
6. 1 __ 5 4 2
7. 1 __ 2 4 3 8. 1 __ 4 4 3 9. 1 __ 3 4 4 10. 1 __ 4 4 5
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MATHEMATICAL PRACTICES
Common Core
5.NF.7.c Solve real world problems involving division of unit fractions by non-zero whole numbers and division of whole numbers by unit fractions, e.g., by using visual fraction models and equations to represent the problem. Also 5.NF.7
Lesson
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Divide 1 _ 2 into 3 equal parts.
1 __ 2 4 3
Each part contains 1 __ 6 of the whole.
So 1 __ 2 4 3 5 1 __ 6 .
Use multiplication to check.
3 3 1 __ 6 5 3 __ 6 5 1 __ 2
Each person gets 1 __ 6 of the casserole.
Problem Solving
11. Sue has 1 __ 2 gallon of milk. She needs to pour 4 glasses of milk.
What fraction of a gallon should she put in each glass?
12. Use Tools Who ran the farthest by the end of the week? Use the table below that shows the distances in miles.
13. Look for Patterns Write two decimals whose product is close to 9.8.
14. Reasonableness Without multiplying, order the following products from least to greatest.
2 3 3 __ 5 1 __ 4 3 3 __ 5 1 2 _ 5 3 3 __ 5 6 __ 6 3 3 __ 5
15. Find the area of the rectangle.
16. What division problem is modeled on the number line below? Find the quotient.
Monday Tuesday Wednesday Thursday Friday
Amir 2 1 __ 2 11 __2 31 __4 13 __4 21 __2
Janie 23 __4 21 __2 33 __4 21 __4 11 __2
MATHEMATICAL PRACTICES
43 Lesson11-5A
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