Multiples of 10
Find the unknown
Division
Parenthesis
Multiplication
100
10 x 1 = a
10 x 2 = b
10 x 3 = c
10 x 4 = d
10 x 5 = e
10 x 6 = f
What pattern do you notice?
a = 10
b = 20
c = 30
d = 40
e = 50
f = 60
We are adding a zero at the end of every number!
100
How can I represent the unknown number in an equation?
By using a letter in the alphabet to show that I do not know that part in the equation.
2 x n = 4
n = 2
100
4 divided by 2 equals what?
4 ÷ 2 = 2
because 2 x 2 = 4
100
What do parenthesis look like? Draw it!
They look like this...
( )
100
What is
9 x 3 = s
s = 27
200
3 x 20 = h
h = 60
Because 3 x 2 = 6
Add a zero on the end we get 60!
200
10 x j = 90
j = 9
10 x 9 = 90
200
Which number comes first in a division equation?
The biggest number, or the product in a multiplication equation comes first in DIVISION.
Product is another word for answer to a multiplication problem.
2 x 2 = 4
4 ÷ 2 = 2
200
What do parenthesis do in math?
Parenthesis help tell you which part in your equation to do first! It is like it is giving you a clue with which part to start with.
(2 x 3) + 10 = 16
Because I would start with the equation inside the parenthesis!
200
7 x 5 = v
v = 35
300
If 5 books cost $20 each, how much money would I need to buy them?
5 x 20 = 100
I would need $100
300
m ÷ 3 = 3
m = 9
9 ÷ 3 = 3
3 x 3 = 9
300
21 ÷ 7 = d
d = 3
3 x 7 = 21
21 ÷ 7 = 3
300
Solve this equation:
(2 x 1) x 10 = d
d = 20
I would do 2 x 1 first because it is inside the parenthesis. I would then get 2, next I have to multiply
2 x 10 to get 20.
300
6 x 6 = ?
36
400
Draw a place value chart
What is 8 x 90?
8 x 90 = 720
400
George's 3 friends all buy different bars of candy. The candy bars each cost $2. How much money did they spend altogether? Use a letter to represent the unknown in your equation.
2 + 2 + 2 = p
4 + 2 = $6
400
g = 64 ÷ 8
g = 8
64 = 8 x 8
8 = 64 ÷ 8
400
Gloria buys 3 boxes of pens. Each box has 2 bundles of 10 gray pens. How many gray pens does she have in the boxes?
She has 60 gray pens.
(3 x 2) x 10 = 60
She has 3 boxes that each have 2 bundles of pens. So 3 x 2 needs to come first, so I used parenthesis. First, 3 x 2 = 6 bundles for 3 boxes
Every bundle has 10 pens, since there are 2 bundles per box, I have to also multiply 2 x 10.
2 x 10 comes after 3 x 2, which is why 10 is not inside the parenthesis! Next, 6 x 10 = 60 pens
400
8 x 9 = r
r = 72
500
If 1 minute is 60 seconds, then how many seconds is 6 minutes and 30 seconds?
(6 x 60) + 30 = 380 seconds
500
6 x c = 42
c = 7
500
The unknown in ALL of these equations is the same, what number is in common with these equations?
12 ÷ n = 4
21 ÷ n = 7
27 ÷ n = 9
3 ÷ n = 1
24 ÷ n = 8
n = 3
because...
4 x 3 = 12
7 x 3 = 21
9 x 3 = 27
1 x 3 = 3
8 x 3 = 24
500
Try this:
(5 x 3) x 3 = h
Then this:
5 x (3 x 3) = f
h =
15 x 3 = 45
f =
5 x 9 = 45
500
Is it true or false that 7 x 9 and 9 x 7 will have the same answer? Why or why not, explain. What is the answer to both equations?
It is true because it does not matter which order the factors are in, this is called that commutative property, they will still have the same answer! The answer for both equations is 63!