The purpose of this lesson is to expand students’ comfort and knowledge in using, computing, and relating with fractions. Students will gain a better understanding of the concepts behind the operations and algorithms we use to multiply and divide fractions.
draw models showing how to multiply and divide fractions
use standards algorithms to perform these operations
translate and solve word problems using these operations
Student Target
“I can multiply and divide fractions.”
CCR Focus Standards
Number and Ratios - Level C
Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.
Apply and extend previous understandings of division to divide unit fractions by whole numbers and whole numbers by unit fractions.
Supporting Standards
Apply and extend previous understandings of multiplication to multiply a fraction by a whole number.
Solve word problems involving multiplication of a fraction by a whole number, e.g., by using visual fraction models and equations to represent the problem. For example, if each person at a party will eat 3/8 of a pound of roast beef, and there will be 5 people at the party, how many pounds of roast beef will be needed? Between what two whole numbers does your answer lie?
Interpret and compute quotients of fractions, and solve word problems involving division of fractions by fractions, e.g., by using visual fraction models and equations to represent the problem. For example, create a story context for (2/3) ÷ (3/4) and use a visual fraction model to show the quotient; use the relationship between multiplication and division to explain that (2/3) ÷ (3/4) = 8/9 because 3/4 of 8/9 is 2/3. (In general, (a/b) ÷ (c/d) = ad/bc.) How much chocolate will each person get if 3 people share 1/2 lb. of chocolate equally? How many 3/4-cup servings are in 2/3 of a cup of yogurt? How wide is a rectangular strip of land with length 3/4 mi and area 1/2 square mi?
Standards for Mathematical Practice
Model with mathematics. (MP.4)
Attend to precision. (MP.6)
KYAE Employability Standards
E.6 Identify and effectively use skills and materials needed for a particular task.
E.7 Accurately analyze information and respond appropriately.
E.8 Interact with others in a professional manner.
