Volume 19

a2+b 2=c 2

Developed by Kristin Hotter Grades 3-5

Using Place Value Discs to Teach Multi-Digit Multiplication Time 45-60 minutes.

Content Use place value discs to break down multi-digit multiplication problems into each of its given parts. In doing this, students will gain a more firm understanding of not just multiplication, but expanded form as well. Utilizing this method will give students another tool and method for solving more complex problems.

Objectives

Materials

Students will…

• Bingo Templates (not included) • Sensational Math™ Place Value Discs 10-Value Student Set (Cat. No. TB24433T) • Worksheet and answer key (attached with lesson plan download)

• Be able to apply their knowledge of place value to solving multi-digit multiplication problems. • Be able to solve multi-digit multiplication problems using a new method. • Be able to examine each numerical value within a given multi-digit multiplication problem.

Common Core State Standards CCSS.Math.Content.4.NBT.B.5 — Multiply a whole number of up to four digits by a 1-digit whole number, and multiply two 2-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models. CCSS.Math.Content.5.NBT.A.1 — Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1⁄10 of what it represents in the place to its left.

For additional FREE lesson plans go to… eNasco.com/math

NP024_17.indd 1

6/2/17 8:21 AM

Introduction 1.

Get students in the multiplication zone by having them warm up with a couple rounds of multiplication bingo. Distribute the bingo templates, then have students fill in the templates with the numbers that you have written on the board. Make sure students use a number only once, and that they know that they will not use all of the numbers. Numbers for the Board: 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 24, 25, 27, 28, 30, 32, 35, 36, 40, 42, 45, 48, 49, 54, 56, 63, 64, 72, 81

2. Once students have filled in the boards, randomly name the following multiplication problems and have them cross off or cover the correct answer to the given problem. You can play bingo for 5-in-a-row, blackout, 4 corners, or any way you choose. Multiplication Problems: (2 x 1), (3 x 1), (2 x 2), (1 x 5), (2 x 3), (4 x 2), (3 x 3), (2 x 5), (3 x 4), (7 x 2), (5 x 3), (4 x 4), (3 x 6), (4 x 5), (8 x 3), (5 x 5), (3 x 9), (5 x 6), (4 x 8), (6 x 6), (8 x 5), (6 x 7), (5 x 9), (8 x 6), (7 x 7), (9 x 6), (7 x 8), (9 x 7), (8 x 8), (8 x 9), (9 x 9)

Activity 1.

Begin with 32 x 42. Ask students how many tens and ones are in 32 (3 tens and 2 ones). Have them take three of the red tens discs and two of the white ones discs and put them at the top of their desks. Follow the same procedure with 42 (4 tens and 2 ones; four red tens discs and two white ones discs). This set of discs should go below the first set of discs on the students’ desks.

2. Students will need to multiply each number in the bottom set of numbers by each number in the top set of numbers. To prepare for this, draw a box on the board where you will write the four products you will come up with as you solve the problem. Tell students they will always start at the bottom right, which is the 2 in 42. Take that and multiply it by the two above it. 2 x 2 = 4, so write 4 in the box.

32 x 42

3. Next, multiply the 2 in 42 by the other number in the top row, which is 30. Since 30 x 2 = 60, write 60 in the box. If students struggle with this, ask them what 3 x 2 is, then add the 0 to the end to get 60. 4. Now it’s time to multiply the 40 on the bottom by both top numbers. First is 40 x 2. Write 80 in the box. Finally, 40 x 30. Point