Relating Relating Multiplication with Multiplication with
DivisionDivision
Relating Relating Multiplication with Multiplication with
DivisionDivision
Let’s Remember:• We know our fact families:
– 5 x 7 = 35 35 = 5 x 7– 7 x 5 = 35 35 = 7 x 5– 35 ÷ 7 = 5 5 = 35 ÷ 7– 35 ÷ 5 = 7 7 = 35 ÷ 5
We also can reverse a multiplication or division number sentence. For example:
We can reverse a multiplication sentence to make a division number sentence. For example:
9 x 11 = 99
99 ÷ 11 = 9
Let’s See that Again45 ÷ 9 = ____
Now, was that so hard?
You TryWrite a Related Multiplication or
Division Sentence:9 x 12 = 108 95 x 4 = 380
450 ÷ 10 = ____ 132 ÷ 11 = ___
Jacob solved the following multiplication equation:
23 x 8 = 184
What number sentence could he use to check his answer?
D 100
23 x 8 = 184
184 ÷ 8 = 23
or 184 ÷ 23 = 8
D 100
Problem Solving – A division problem that
you can solve with multiplication
Last year there were a total of 78 students in the 4th grade classes of Encarnacion, Boynton and Hamme. If each class has the same number of students, how many students were in each class?
Think – “Zzzz”There are a total of 78 students in the 4th
grade classes of Encarnacion, Boynton and Hamme. If each class has the same number of students, how many students are in each class?
Division – I know the total78 ÷ 3 = ?
? x 3 = 78
Tutters says, “Meowwww… it’s your turn!”
D 200
Gabrielle solved the following math problem:32 x 4 = 128
What number sentence could she use to check her answer?
128 128 ÷ 4 = 32÷ 4 = 32
32 x 4 = 128
D 200
• Now – don’t let the variables in the next problems scare you!
D 400
If 48 ÷ n = 6
What does 6 x n = ?
48
because n = 8
48 ÷ 8 = 6
6 x 8 = 48
D 400
True or False
The following statement is correct:
If n x 3 = 18, then n = 18 ÷ 3
D 300
True
because…
If n x 3 = 18, then n = 18 ÷ 3
n = 6
6 x 3 = 18
6 = 18 ÷ 3
D 300
ZZZZ
N x 3 = 18
True or False
The following statement is correct:
If 5 x f = 35, then 35 = 5 ÷ f
D 300
False
because…
If 5 x f = 35, then f = 7
And 35 = 5 ÷ 7?
NO WAY!
D 300
ZZZZZZ
5 x f = 35
Focused and alert, no sleeping now!
So… if all I have to do is reverse the number sentence?
• What is another way to write the equation 308 ÷ n = 14 ?
a. 14 + n = 308b. 14 x 308 = nc. 14 x n = 308d. 308 – 14 = n
(Let’s just reverse the number sentence in the question. 14 x n = 308, so c is our answer!)
Well, how about with variable
NWhat is another way to write the equation
N x 24 = 120?
a. N = 24 ÷ 120
b. N = 120 ÷ 24
c. N = 24 x 120d. N x 120 = 24 (Let’s just reverse the number
sentence in the question. 120 ÷ 24 = N, so b is our
answer!)
What is another way to write the
equation 54 ÷ n = 6?
a. n = 9 x 6b. n = 54 x 6c. n = 54 ÷ 6d. n = 54 x 9
(THINK – What number could n be? Which answer choice makes sense for that number?)
• Write a related equation for the following number sentences:
36 ÷ 6 = 6 25 ÷ 5 = 572 = 9x 8 6 x 7 = 42
y ÷ 4 = 5 3 x b = 6c = 8 x 2 d ÷ 10 = 9
– Find the value of the variable (letters) in the last four equations.
Which statement is correct?
A. If a ÷ 3 = 7, then a = 7 x 4
B. If 5 x 6 = b, then 6 x b = 5
C. If 14 ÷ y = 2, then y = 14 x 2
D. If d = 24 ÷ 6, then d x 6 = 24
D 500
Recommended