Math 5.1 (x 10, 100)
Math 5.2 (x 10 and 100)
Math 5.3 (Break Apart to X)
Math 5.4 (Mental Math to X)
Math 5.5+5.6 (Estimate + Reasonableness).
100
If Anna has 4 sheets of stickers and each sheet contains 10 stickers, how many stickers does she have?
Draw the array as well as giving the answer.
40
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100
Fill in the blanks:
To find 6 x 200, first multiply _______. Then, add ____ zeroes at the end. The answer is ______.
First multiply: 6x2 = 12.
Then add 2 zeroes at the end.
The answer is 1,200.
100
Find the partial products, then solve.
8 x 24.
8 x 20 = 160
8 x 4 = 32
160 + 32 = 192.
100
Use mental math (compensation) to solve 18 x 9.
18 x 9 turns in to 18 x 10
18 x 10 = 180
Subtract one group of 18 from 180
180 - 18 = 162.
100
Drop your markers!
Challenge round: Each group member should solve 2 of the 8 listed problems. First two groups to solve and have all the answers correct gets triple points.
Estimate and solve:
41 x 3 248 x 4 38 x 5 498 x 2
87 x 9 102 x 8 88 x 3 28 x 6
Estimate + solve.
40 (41) x 3 = 120
90 (87) x 9 = 810.
250 (248) x 4 = 1,000
100 (102) x 8 = 800
40 (38) x 5 = 200
90 (88) x 3 = 270
500 (498) x 2 = 1,000
30(28) x 6 = 180
200
Find 5x10.
Draw the array. (think _ groups of __).
50.
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200
Find the product of 8 x 900.
7,200.
200
What addition sentence shows how to use partial products to find 3 x 18?
A) 3 + 21 = 24
B) 30 + 24 = 54
C) 31 + 23 = 54
D) 10 + 24 = 34
18 x 3
Break the tens apart. 10 x 3 = 30.
Multiply the ones. 8 x 3 = 24.
30 + 24 = 54.
200
DOUBLE POINTS:
To multiply 4 x 148, James first multiplied 4 x 150 and got 600. How much should James subtract from 600 to find the product of 4 x 148?
James should subtract 4 groups of 2.
4 x 2 = 8.
600 - 8 = 592.
200
DOUBLE POINTS (must include correct explanation).
What is the closest estimate for 7 x 78? Explain.
A) 80 x 7 = 560
B) 78 x 10 = 780
C) 78 x 5 = 390
D) 75 x 10 = 750
A) 80 x 7 = 560
Estimating isn't exactly accurate, but you want the closest answer to the product as possible. To do that, you want to use multiples of 10 and 100, and 78 is pretty close to 80, which is a multiple of 10.
7 x 78
To double check using compensation...
70 x 7 = 490
8 x 7 = 56
490 + 56 = 546
300
What math equation represents this table?
7
7
7x7, which is 49.
300
When explaining how to solve for 3 x 700, what is the first step you would do?
Solve for your basic fact. (3x7 = 21).
300
Write the addition statement for 75 x 6
70 x 6 = 420
5 x 6 = 30
Addition statement would be 420 + 30.
300
Use compensation to multiply 52 x 9.
Double points for showing two ways & explaining.
Two ways:
1) Take away (subtract) 2 groups of 9 to make 50 x 9. Use basic fact to find out 5x9 = 45, add the 0.
450. Then add your 2 groups of 9 (18)
450 + 18 = 468.
2) Add one group of 52 to make 52 x 10 (520). then take away one group of 52
520 - 52 = 468.
300
Mr. Lu makes 78 out of 100 free throws in one session. What is a reasonable amount of free throws he'll make in five sessions?
Sentence starter: _______ (product) because ___ x __ is about _ x __ = __.
400 because 78 x 5 is about 80 x 5 = 400.
400
How many zeroes are in the product of 8 x 500? Explain.
5x8 = 40 (basic fact). Add two zeroes (500), which is 4,000. 3 zeroes are in the product.
400
Write three multiplication sentences using at least one multiple of 10 or 100 that would get you a product of 1,600.
Example multiplication sentences would be...
4 x 400
40 x 40
16 x 100
2 x 800
80 x 20
400
DOUBLE POINTS:
What partial products will help you find the product 8 x 104? Solve after you've written the partial products.
8 x 100 = 800
4 x 8 = 32.
800 + 32 = 832.
400
Solve 99 x 8. Explain.
Add one group of 8 to make 100 x 8, which equals 800. (basic fact 8x1, add two zeroes).
Then take away one group to make 800 - 8, which equals 792.
400
A classroom in Camino Grove can hold about 32 students. There are 4 classrooms for 4th graders. What is a reasonable estimate of the amount of 4th graders can Camino Grove enroll?
120, because 32 x 4 is about 30 x 4 = 120.
500
Allison has 10 groups of chips with 4 in each group. Moses has 3 groups of chips with 10 in each group. Who has more chips? Explain through pictures.
Moses:
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30.
Allison:
xxxx xxxx xxxx xxxx xxxx
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40.
500
Drop your markers!
Challenge round: Each group member will solve 2 out of the 8 listed problems. You will have 1:30 to complete it. Every group that completes it will receive the 500 points.
6 x 700 40 x 2 500 x 6 80 x 8
4 x 800 4 x 500 300 x 9 3 x 200
6x700 = 4,200
4x800 = 3,200
40 x 2 = 80
4 x 500 = 2,000
300 x 9 = 2,700
80 x 8 = 640
3 x 200 = 600.
500
Mr. Lu is attempting to count all of the students in Camino Grove. If they are lined up in 6 rows with 122 students in each row, how many students are there in the school?
Solve using partial products.
100 x 6 = 600
20 x 6 = 120
2 x 6 = 12
600+120+12 = 732 students in Camino Grove.
500
Find the mistake:
Anthony used compensation to find the product of 38 x 6. First, he found 40 x 6 = 240. Then he changed the product by adding 2 groups of 6 to get 252. What did he do incorrectly?
Instead of adding 2 groups of 6, he should be subtracting.
240 - 12 = 228.
500
If Alex practiced soccer for 13 hours every week for 9 weeks. About how many hours did he practice in all?
How can you check your answer?
13 x 9 would estimate to 13 x 10 = 130 hours.
To check, use compensation.
10 x 9 = 90
3 x 9 = 27.
90 + 27 = 117 hours.