Magnitude Estimate
Multiplication
Partial-Sums Method
Partial-Difference Method
Story Problems
100
Find the magnitude estimate for the following: 7 X 33
What is 10 X 30 = 300
100
Find the magnitude estimate and solve the problem. Show your work! 46 X 73
What is 50 X 70 = 3,500 46 X 73 = 3,358
100
Solve using the partial-sums method. 25 + 43
What is 20 + 40 = 60 5 + 3 = 8 Answer = 68
100
Solve using the partial-difference method. 88 - 42
What is 80 - 40 = 40 8 - 2 = 6 40 + 6 = 46
100
Chloe went to the store and spent $5 on oranges. Jennifer spent $9 on apples. How much did Chloe and Jennifer spend all together?
What is $5 + $9 = $14
200
Find the magnitude estimate for the following: 234 X 389. Round to the nearest hundred.
What is 200 X 400 = 80,000
200
Find the magnitude estimate and solve the problem. Show your work! 371 X 7
What is 400 X 10 = 4,000 371 X 7 = 2,597
200
Solve using the partial-sums method. 233 + 737
What is 200 + 700 = 900 30 + 30 = 60 3 + 7 = 10 900+60+10=970
200
Solve using the partial-difference method. 973 - 342
What is 900 - 300 = 600 70 - 40 = 30 3 - 2 = 1 600 + 30 + 1 = 631
200
Caleb bought a new video game. The video game was $22 total. Caleb paid with a $50 bill. How much money did Caleb get back in change?
What is $50 - $22 = $28
300
Find the magnitude estimate for the following: 1,025 X 22. Round to the nearest thousand & the nearest tens.
What is 1,000 X 20 = 20,000
300
Find the magnitude estimate and solve the problem. Show your work! A pencil company is shipping 822 cases of pencils to Rock River Intermediate School. Each case contains 29 boxes. How many boxes of pencils are needed?
What is 800 X 30 = 24,000 822 X 29 = 23,838 boxes of pencils
300
Solve using the partial-sums method 1,238 + 1,651
What is 1,000 + 1,000 = 2,000 200 + 600 = 800 30 + 50 = 80 8 + 1 = 9 2,000 + 800 + 80 + 9 = 2,889
300
Solve using the partial-difference method 8,745 - 3,324
What is 8,000 - 3,000 = 5,000 700 - 300 = 400 40 - 20 = 20 5 - 4 = 1 5,000 + 400 + 20 + 1 = 5,421
300
Isaiah was making lunch for 5 friends. He started with a dozen eggs. He bought 10 more. How many eggs did he cook for lunch? What is the open number sentence for this story problem?
What is 12 + 10 = E Solution: E=22 Answer: 22 eggs
400
Find the magnitude estimate for the following: 4.4 X 8.5
What is 4 X 9 = 36
400
Find the magnitude estimate and solve. Show your work! 8.9 X 5.5
What is 9 X 6 = 54 8.9 X 5.5 = 48.95
400
Solve using the partial-sums method. 3.48 + 5.51
What is 3 + 5 = 8 0.4 + 0.5 = 0.9 0.08 + 0.01 = 0.09 8 + 0.9 + 0.09 = 8.99
400
Solve using the partial-difference method. 9.56 - 4.32
What is 9 - 4 = 5 0.5 - 0.3 = 0.2 0.06 - 0.02 = 0.04 5 + 0.2 + 0.04 = 5.24
400
Meagan has a $20 bill. She bought a cheeseburger that cost $2.54 and a glass of lemonade that cost $1.97. How much change did she receive? Show your work!
What is $20 - ($2.54 + $1.97) = X $2.54 + $1.97 = $4.51 $20 - $4.51 = $15.49
500
Find the magnitude estimate for the following: 9.4 X 0.52
What is 9 X 1 = 9
500
A group of 29 students is going to walk 2.2 miles each for gym class. How many total miles is this in all?
What is 30 X 2 = 60 29 X 2.2 = 63.8 miles
500
Solve using the partial-sums method. 32.97 + 49.58
What is 30 + 40 = 70 2 + 9 = 11 0.9 + 0.5 = 1.4 0.07 + 0.08 = 0.15 70 + 11 + 1.4 + 0.15 = 82.55
500
Solve using the partial-difference method. 7.64 - 3.79
What is 7 - 3 = 4 0.6 - 0.7 = -0.1 0.04 - 0.09 = -0.05 4 - 0.1 - 0.05 = 3.85
500
Mrs. Schmidt needs 4 pieces of ribbon. Each piece has to be a different length. She needs pieces that measure 32 cm, 44 cm, 58 cm, and 25 cm. If she starts with 200 cm of ribbon, how much is left over? Show your work!
What is 200 - (32 + 44 + 58 + 25) = X 32 + 44 + 58 + 25 = 159 200 - 159 = 41 Solution: X = 41 Answer: 41 cm
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