Multiply and Divide with Familiar Facts
Videos to help Grade 3 students learn how to multiply and divide with familiar facts using a letter to
represent the unknown.
Common Core Standards: 3.OA.4,
Plans and Worksheets for Grade 3
Plans and Worksheets for all Grades
Lessons for Grade 3
Common Core For Grade 3
New York State Common Core Math Module 3, Grade 3, Lesson 3
Twenty-four people line up to use the canoes at the park. Three people are assigned to each canoe.
How many canoes are used?
Note: Students may choose to model either as division or as multiplication. In the Concept Development this problem provides a context for using a letter to represent the unknown.
instead of a question mark. For this problem, we might choose letter c to help us express that the unknown stands for how many canoes are used in the problem.
How will using a letter to express the unknown value change the way we model and solve?
Problem 1: Use a letter to represent the unknown in multiplication.
Problem 2: Use a letter to represent the unknown in division.
Twenty-one students are grouped in threes to go on a field trip. How many groups of students are there?.
Lesson 3 Homework
1. a. Complete the pattern.
b. Find the value of the unknown.
10 × 2 = d
d = 20
10 × 6 = w
3 × 10 = e
10 × 7 = n
f = 4 × 10
g = 8 × 10
p = 5 × 10
2. Each equation contains a letter representing the unknown. Find the value of the unknown.
Lesson 3 Homework
3. Pedro buys 4 books at the fair for $7 each.
a. What is the total amount Pedro spends on 4 books? Use the letter b to represent the total amount
Pedro spends, and then solve the problem.
b. Pedro hands the cashier 3 ten dollar bills. How much change will he receive? Write an equation to
solve. Use the letter c to represent the unknown.
4. On field day, the first grade dash is 25 meters long. The third grade dash is twice the distance of the first
grade dash. How long is the third grade dash? Use a letter to represent the unknown and solve.
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