Students will be able to write and solve word problems that require the multiplication of fractions by whole numbers.
- Pose the following word problem to students: Sally ate 1/8 of a pie. Suzy ate 3 times more than Sally. How much of the pie did Suzy eat?
- Have students talk with each other about how they would solve this word problem.
- Call on some students to share how they would solve the problem. Explain that students could use either multiplication or addition. Remind students that repeated addition is another form of multiplying, so multiplication is the most efficient way to solve this problem.
- Explain that today, students will be learning how to multiply fractions by whole numbers. They will also be writing their own word problems that require this type of math.
Explicit Instruction/Teacher modeling(5 minutes)
- Revisit the word problem given at the beginning of the lesson. Write "1/8x3" on the board.
- Explain that when multiplying fractions by whole numbers, the first step is to represent the whole number as a fraction. Remind students that all whole numbers can be represented as a fraction by putting a "1" in the denominator. Rewrite the problem as "1/8x3/1."
- Show students that in order to multiplying these two fractions, they simply need to multiplying the numerators together and then multiply the denominators together to get the product: 3/8.
- Show one more example with 2/5x2.
Guided Practice(15 minutes)
- Tell students that when solving word problems, it is important to look for key words to indicate what operation will be used. Ask students what key word was used in the word problem at the beginning of this lesson that indicated multiplication would be used? Answer: times.
- Have students talk with a partner about some other key words that would indicate multiplication.
- Write a list on the board of multiplication key terms. You might include: product, multiplied, by, double, and twice.
- Pass out the Fraction Word Problem worksheet to each student. Have students work together to complete the worksheet. Students should also circle the key multiplication word in the word problem.
- Review each step of the worksheet with students when they are finished.
Independent working time(15 minutes)
- Hand out lined paper to each student.
- Explain that students will be writing their own word problems that involve multiplying a fraction by a whole number.
- When they are finished, students must also solve their word problem at the bottom. Remind students that they must show their work!
- Encourage students to use the "key terms" list on the board to help them as they write their word problems.
- Circulate the room to ensure that students' word problems require multiplication of fractions and whole numbers.
- When they finish, students can share their word problems for their classmates to solve.
- Encourage students to be creative with their word problems!
- Enrichment: Have students simplify their answers after solving the problem. You could also encourage these students to write word problems that have a whole number as the answer.
- Support: Give these students sentence stems to help them write their word problem. For example: [Name] sells [fraction] of [item]. [Name] sells [whole number] times as much. Additionally, some students may struggle with the actual multiplication of fractions. Continue practicing example problems with these students.
- Look at students' word problems to determine if they were able to write a word problem that requires multiplying a whole number by a fraction. Their answers will also indicate whether or not they understand how to multiply a fraction by a whole number.
Review and closing(5 minutes)
- Have some students share their word problems with the entire class.
- As students share, the rest of the class should write down the problem represented by the story and solve it.