Lesson: Multiply: Repeated Addition
SWBAT use repeated addition to solve a multiplication problem.
Materials Needed: DN Worksheet, white board, dry erase markers, student slate boards, and IND Worksheet.
Vocabulary: multiplication, array, model, group, counting, product, multiple
Do Now (3 -5 min): Teacher hands a DN Worksheet to every student and asks the students to complete the worksheet independently.
Opening (2 -3 min): Teacher quickly reviews answers to the Do Now and then says, “Today, we are going to begin learning about multiplication. I believe many of you have already started practicing multiplication. By the end of this lesson, you will be able to use repeated addition to solve a multiplication problem.”
Direct Instruction/ Guided Practice (15 min): Teacher writes the multiplication array on the board (3 x 4). The teacher begins by saying, “Yesterday, I told you all you needed to now to get multiplication was counting. Well, that is true, but there is a faster way to get the answers to your multiplication problems…. Addition! We all know how to add, so let’s learn about another strategy to help us get our multiplication facts down.” The teacher then directs the students attention to the multiplication array. “I am going to make this multiplication array into a repeated addition problem, which will help me answer the problem. Watch as I do this.” The teacher writes 3 + 3 + 3 + 3 = ? under the multiplication array. “Yesterday we learned that multiplication is about groups of numbers, so this array was telling me that 4 groups of 3, so to write that as an addition problem, or repeated addition I write +3 for times. Ok, so now that I have translated my multiplication array into an addition problem I can solve the multiplication problem. 3+ 3 = 6, 3 + 3 = 6, so 6 + 6 = 12. My answer is 12! Alright, let’s try this by only looking at a multiplication fact.” The teacher writes 4 x 6 on the board. “Ok, so I have my multiplication fact. Who can tell me what this multiplication fact is asking me for, remember multiplication is about groups. [The problem is asking for 4 groups of 6]. Great job! So to translate that into an addition problem I am going to add 6 4 times, because that is how many groups the problem calls for. Question! Does it matter if I make 6 groups of 4? [Answers will vary]. The correct answer is no! When we are working with multiplication it does not matter the order of the numbers, we will always get the same answer if we use the two numbers, so 4 groups of 6 is the same as 6 groups of 4. Let’s write it as an addition problem now. 6 + 6 + 6 + 6 = ?. Let’s solve 6 + 6 = 12, 6 + 6 = 12, so 12 + 12 = 24!”
The teacher then passes out slate boards to each of the students. The teacher and students will work on 5 problems together before IND Practice. The teacher should reveal the problem and then have the students translate it into a repeated addition problem before solving.
6 x 3 = ?
2 x 8 = ?
4 x 9 = ?
5 x 6 = ?
7 x 3 = ?
Then the teacher should pose these types of questions to the students and have them convert the repeated addition into a multiplication problem.
4 + 4 + 4 + 4 + 4 = _____ x ______
7 + 7 +7 +7 = _______ x ________
5 + 5 + 5 = _________ x _________
3 + 3 + 3 + 3 + 3 + 3 = _________x __________
2 + 2 + 2+ 2+ 2+ 2 = ___________x__________
Independent Practice (10 min): Each student is given the IND Worksheet and asked to complete it individually and turn it in.
Closing (2-3 min): Teacher calls the attention of the students back toward the front of the class to ask what they learned about.
|IND Lesson 2 Multiplication Classwork|
|DN lesson 2 arrays Starter / Do Now|