Open Number Line
Solve 5 x 20 using an open number Line
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5 jumps of 20
20, 40, 60, 80, 100
Write an equivalent equation for 5 x 70 using the distributive property of multiplication
Sample may vary:
5 x 70 = (2 x 70) + (3 x 70)
5 x 70 = (4 x 70) + (1 x 70)
5 x 70 = (5 X 30) + (5 x 40)
5 x 70 = (5 X 20) + (5 x 50)
5 x 70 = (5 X 10) + (5 x 60)
4 x $30
4 x (3 x 10) = (4 x 3) x 10 = $120
What is the Associative property of multiplication?
The Associative property of multiplication says factors in a multiplication equation can be grouped in any order and the product will be the same.
What is a multiple of 10?
#8 Alice reads 50 pages each day. How many pages does she read in 7 days?
Use the open number line to solve.
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7 jumps of 50 =350 pages
What is the basic fact of 9 x 60
9 x 6
Information
Trimming bushes - $20
Weeding flower bed- $20
Franklin trimmed bushes for 2 neighbors and weeded flower beds for 3 neighbors. How much did Franklin earn?
trimming- 2 x $20- 2 jumps of 20 = 20, 40
weeding -3 x $20- 3 jumps of 20 = 20, 40, 60
40 from trimming + 60 from weeding= $100
#7 To solve 6 x 40, Heidi wrote
6 x (4 x 10)=(6 x 4) x 10
What is 6 x 40
6 x 40 = 240
7 x 50
350
Use an open number line to solve
4 x 90
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4 jumps of 90
90, 180, 270, 360
#10 Choose all of the expressions that are equal to
3 x 60
a. (3 x 6) x 10 d. 18 x 10
b. 9 x 10 e. 6 x (3 x 10)
c. 36 x 10
a. (3 x 6) x 10
d. 18 x 10
e. 6 x (3 x 10)
#4 Betty is making bracelets and needs 6 boxes of blue beads and 2 boxes of white beads. Each box of beads contains 20 beads.
How many beads does Betty need?
6 + 2 = 8
8 x 20 = 160 beads
#6 on Review Worksheet
Draw lines to connect equal expressions
5 x 60----------- 30 x 10
6 x 60----------- 36 x 10
5 x 80----------- 40 x 10
6 x 80----------- 48 x 10
What is short cut for multipling by ten.
the product is the other factor that is not ten with a zero after it, in the ones place
#11 Bethany earns $40 babysitting on Saturday. How much does Bethany earn for babysitting on 4 Saturdays?
Use a number line to solve the problem.
Show another way to solve the problem.
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4 jumps of 40
0, 40, 80, 120, 160
$160
Associative Property
4 x 40 = (4 x 4) x 10 =160Distributive Property
4 x 40 = (2 x 40)+(2 x 40) = 160
#2 Which equations are equal to 7 x 40
a.(7 x 4) x 10
b. (7 + 4) x 10
c. 4 x 70
d. 7 x (4 x 40)
a.(7 x 4) x 10
c. 4 x 70
#9 The subscription to a children's magazine is $30 per year. Jane sold 7 subscriptions.
What was the total cost of the subscriptions?
Explain how you can use structure to solve.
I can use a rule to multiply by multiples of 10.
First I multiply the basic multiplication fact.
7 x 3 = 21
Then I write a zero after the product.
7 x 30 = 210
Use the Associative Property of Multiplication to group factors of 7 x 60 and solve
7 x 60 = 7 x (6 x 10)
(7 x 6) x 10
42 x 10
420
write all the multiples of Ten from 1- 100
10, 20, 30, 40, 50, 60, 70, 80, 90, 100
#1 Adam gives each of his 5 friends a baseball card album. Each album holds 30 cards. How many cards can the albums hold in all?
-Use the open number line to solve.
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5 Jumps of 30
5x30=150 baseball cards
Complete #5 on the review worksheet
4 x 50 8 x 40
(4 x 5) x 10 (8 x 4) x 10
20 x 10 (4 x 8) x 10
5 x (4 x 10) 32 x 10
(5 x 4) x 10 4 x (8 x 10)
#3 Mr. Blaine is building a deck and bought 9 boxes of bolts. There are 40 bolts in each box.
How many bolts did Mr. Blaine buy? Explain how to solve.
9 x 4 = 36
9 x 40 = (9 x 4) x 10 = 36 x 10 = 360
360 bolts
Find 4 x 80. Decompose a factor.
Write 4 as 2 + 2
4 x 80= (2 + _____) x 80
= ( 2 x 80) + ( 2 x 80)
= 160 + 160
= 320
Complete the multiplication table
X 10 20 30
7 70 140 ?
8 80 ? ?
9 ? 180 ?
As you move down the columns, the numbers __________ by the value of the column.
X 10 20 30
7 70 140 210
8 80 160 240
9 90 180 270
As you move down the columns, the numbers increase by the value of the column.