Lesson 35: Multiplication Facts
Lesson Objectives
- Use objects, pictures, drawings, and number lines to understand multiplication
- See multiplication as repeated addition
- Use addition to find the total number of objects and dots in arrays
- Write equations of repeated addition and multiplication
- Apply skip counting and the TouchMath approach for finding products
- Apply vocabulary (factors and products) in explaining multiplication
- Apply the commutative property to multiplication
- Use arrays as a strategy for skip counting
- Use strategies, including repeated addition and skip counting, to find products
Materials
- Extend Workbook (Page 35)
- Counters or manipulatives
- Highlighters, markers, or crayons
- TouchMath’s Foam Numerals and TouchPoints (for more concrete)
- Skip counting multiplication songs (multiples of 5) (as needed)
Step 1: Warm Up (5 min)
Then, use a number line 0-20. Review skip counting by 2’s. Have them look at the sequence and point out that when skip counting on 2’s, that the first two 2’s make 4, and in other words means 2+2. Explain that skip counting is adding multiple addends – the same addend over and over. It is easier to skip count than to add all of the addends when we get to larger numbers. Explain that this also means we are adding groups of the same number of items together. Review prior vocabulary showing a few multiplication problems with visuals (e.g. arrays) and going through each part (factor x factor = product), look at the groups of dots and circle/ring, count the number of items in each group to determine the factors (3 groups of 5 = 15 total items). Review that multiplication is repeated addition (5+5+5, but also if factors are reversed, the result is same product (3+3+3+3+3). Optional: review skip counting songs for multiples of 5.
Step 2: Vocab Review (5 min)
Review prior vocabulary: repeated addition, arrays (an arrangement of a set of numbers or objects in rows and columns) products of multiplication problems, and factors (a number that you multiply with another number to get a product), and skip counting. Remind students that skip counting is a tool that will help us find pairs of equal addends. It is also the foundation of multiplication. Remind them of even numbers: Even numbers always have two equal addends. For example, 8 has two equal addends, 4 + 4. The number 20 has two equal addends, 10 + 10. We will find ways to identify the two equal addends for even numbers.
Step 3: Model (5 min)
Find a skip counting song (by 2 and 5) and remind students about the importance of skip counting. See if any students feel comfortable skip counting by 2’s or 5’s now. Ask students to skip count backwards, after practicing forward (using number lines, as needed). Then, practice skip counting: take counters and divide 10 into two equal sections. Ask students to tell you how many counters are in each group (5) and then ask how many groups are there total (2). Tell students that this is the same thing as 5+5, which equals 10 total counters. Show several examples skip counting using counters or manipulatives, skip counting forward and backwards. You may choose to review commutative property of multiplication as well, or review teaching how to skip count by one number while touching the TouchPoints on the other number, using TouchMath’s Foam Numerals.
Step 4: Guided Practice (5 min)
Distribute a 100s chart, and start on 2. Ask students to skip count by 2’s forward to 20. Have them circle each number with a red marker. Then, ask them to skip count by 2’s backwards from 40 to until they get to 20. Have them circle each number with a yellow marker to see the difference between skip counting forward, and skip counting backward. In groups, ask students to draw arrays with dots/circles/dots with multiples of 2’s and 5’s for review (5x3 4x2, 5x6, 2x7, etc.). Have students circle each group. Ask them, “how many groups of dots/stars did you circle? How many dots/stars are in each group?” Then have them write down their multiplication sentences/problems next to their arrays (e.g. “We circled 3 groups of dots and there are 5 dots in each group. Therefore, my multiplication sentence is 3x5=15. There are 15 total dots altogether. This means the product of 5+5+5 is 15”). Ask what the repeated addition statements would look like (e.g. 5+5+5 OR 3+3+3+3+3). Have students practice skip counting by one number while touching the TouchPoints on the other number using TouchMath’s Foam Numerals.
Step 5: Student Practice (5 min)
Go to Student Workbook Page (35). Read the directions at the top of the page. Tell students they will be practicing multiplication problems with multiples of 2’s and 5, by skip counting, using arrays, and with repeated addition. For the first half of the page, ask students to find the products of the multiplication problems for multiples of 2’s. They should notice that each problem is just skip counting by 2’s, or moving up by 2’s. Students will then complete the second half of the page, first by determining how many groups of dots there are (4 groups of 5 dots), and then filling in the repeated addition statement (5+5+5+5 = 20), and understanding that the sum of the repeated addition statement is the same as the product of 5×4. Repeat these steps for the next problem.
Step 6: Wrap Up (5 min)
To wrap up the lesson, review the learning objectives and core vocabulary words again and ask your students about their experience.
