# Multiplication and Division, Part 1

## Objective

Build fluency with multiplication and division facts using units of 4.

## Common Core Standards

### Core Standards

?

• 3.OA.A.1 — Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each. For example, describe a context in which a total number of objects can be expressed as 5 × 7.

• 3.OA.A.2 — Interpret whole-number quotients of whole numbers, e.g., interpret 56 ÷ 8 as the number of objects in each share when 56 objects are partitioned equally into 8 shares, or as a number of shares when 56 objects are partitioned into equal shares of 8 objects each. For example, describe a context in which a number of shares or a number of groups can be expressed as 56 ÷ 8.

• 3.OA.B.5 — Apply properties of operations as strategies to multiply and divide. Students need not use formal terms for these properties. Example: Knowing that 8 × 5 = 40 and 8 × 2 = 16, one can find 8 × 7 as 8 × (5 + 2) = (8 × 5) + (8 × 2) = 40 + 16 = 56. (Distributive property.) Example: If 6 × 4 = 24 is known, then 4 × 6 = 24 is also known (Commutative property of multiplication.) 3 × 5 × 2 can be found by 3 × 5 = 15, then 15 × 2 = 30, or by 5 × 2 = 10, then 3 × 10 = 30. (Associative property of multiplication.)

• 3.OA.C.7 — Fluently multiply and divide within 100, using strategies such as the relationship between multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40 ÷ 5 = 8) or properties of operations. By the end of Grade 3, know from memory all products of two one-digit numbers.

## Criteria for Success

?

1. Skip-count by fours.
2. Solve multiplication, division, and missing factor problems involving four by skip-counting. (Note: this includes problems where 4 is listed as the first factor, implying the use of the commutative property.)

#### Fishtank Plus

• Problem Set
• Student Handout Editor
• Vocabulary Package

?

### Problem 1 How many?

#### References

flickr Photo: iPhone Home Screens, August 7, 2014 by Lee Bennett

iPhone Home Screens, August 7, 2014 by Lee Bennett is made available on flickr under a CC BY-NC-SA 2.0 license. Accessed Oct. 12, 2018, 9:59 a.m..

### Problem 2

Solve.

a.     $4\times 9 =$ ___

b.     ___ $= 24 \div 4$

c.     ___ $\times 4 =12$

## Discussion of Problem Set

?

• How did the skip-counting sequence in #1 help you solve the other problems on the Problem Set?
• What do you notice about #3b and #3c? What do you wonder?
• How did the commutative property help you to solve the equations in #7?
• Is division commutative? How do you know?
• Write the twos skip-counting sequence. Write the fours skip-counting sequence. What do you notice? What do you wonder?

1.   $8\times 4 =$ ____                  2.   ____ $= 28 \div 4$               3.   $4\times$ ___ $=8$