Multiplication
6 x 2 =
12
21 ÷ 7 =
3
There are 2 lines. Each line has 7 students. How many students are there in total?
7 x 2 = 14
There are 14 students.
Give an example of the commutative property (flip trick).
Answers will depend.
6 x __ = 0
3 x __ = 0
4 x __ = 0
0. Everything x 0 = 0
36 ÷ 9 =
4
Ben has 30 cards. He wants to put them equally into 3 boxes. How many cards will go into each box?
30 ÷ 3 = 10
10 cards
How can you make solving 8 x 9 easier if you did not memorize it? (Split trick).
Break apart 9 = 5 + 4.
8 x 5 + 8 x 4
40 + 32 = 72
How do you know to use division given a word problem?
If you are given the total and either the number of groups or size, it is division.
If you share something equally, it is division.
If you split or cut something equally, it is division.
8 x __ = 48
6
____ ÷ 6 = 7
42
Ms. Allen has 30 students. Each student needs 2 pencils. How many pencils are needed for the class?
2 x 30 = 60
60 pencils
Because 3 and 27 are odd numbers, but 256 is an even number. odd x odd = odd.
3 x (4 x 50)= 50 x (3 x M)
What does M equal?
M = 4
40 x 4 =
160
60 ÷ 3 =
20
Books: $7
Magazines: $5
Maggie wants to buy 3 books and 3 magazines. How much money does it all cost?
7 x 3 = 21
5 x 3 = 15
21 + 15 = 36
$36
Ben says 32 x 5 = 153. He is wrong. How do you know?
Because ___ x 5 will always end with a 0 or a 5.
Which of the following equals 8 x 3? Pick all that apply.
A. 3 x 8
B. 3 x (5 + 3)
C. 6 x 4
D. 9 x 2
A., B., C all equal 24
9 x 60 =
540
240 ÷ 80 =
Lorena has asked for 3 big buses and 1 small bus for a field trip. Each big bus can hold 40 students and the small one can hold 20 students. How many students will fit into the buses?
3 x 40 = 120
1 x 20 = 20
120 + 20 = 140
140 students
Ben says that you can use parentheses to make 3 x 12 easier. He is right. Break apart 12 to solve 3 x 12.
3 x 12 = 3 x (2 x 6)
= (3 x 2) x 6
= 6 x 6
= 36
Solve 3 x 14.
3 x 14 = 3 x (2 x 7)
= (3 x 2) x 7
= 6 x 7
= 42