Multiplying Multiples of 10
Solve 80 x 50.
4,000
Estimate the product of using rounding 27 x 21.
600
Use a strategy (Partial Products, Area Model, or an Array Using Place Value Blocks) to find the following product: 56 x 17
952
One school has 60 buses. Each school bus carries 34 students. If all of the school buses are full, how many students are on the school buses?
2,040 students
A store has 57 sheets of stickers and each sheet has 12 stickers.
Makenzie broke 57 into 50 + 7 and wrote
(50 x 12) + ( 7 x 12) to find the total number of stickers. What property did she use?
Distributive Property
Solve 30 x 90.
2,700
Estimate the product of 53 x 32 using rounding, then compatible numbers.
1,500
55x30 = (50x30) + (5x30) = 1500+150= 1650 (Accept other acceptable answers)
Use an area model to solve the following: 84 x 37
3,108
(Check models)
Give at least 3 expressions that are equal to 460.
Examples:
46x10
(40+6)x10
23x20
Mia gets paid $15 each time she walks her neighbor's dogs. She plans to walk them for the next 12 weeks.
Which equations can Mia use to find the amount of money she will earn? Choose all that apply.
A. $15 x 12 = m C. $15 x ( 10 + 2) = m
B. 12 + $15 = m D. 15 x (10 x 2) = m
A and C
Solve 60 x 21.
1,260
Estimate the product of 98 x 42 three different ways.
4,000 (accept all reasonable answers)
Use partial products to solve the following: 72 x 64
70x60=4200
2x4=8
70x4=280
2x60=120
4,608
There are 27 students in Ms. Langley's class. Each student is assigned 23 different math problems. How many math problems are assigned to the whole class? Draw an area model to show your work.
621 math problems
Estimate the product of 93 x 42. Then find the exact amount.
3,600
3906
The product of two factors is 7,200. If one of the factors is 90, what is the other factor?
80
About how many gallons of water are used to refill a bathtub everyday for 41 days? (A tub is full with 57 gallons of water). Give two ways to estimate. Which estimate will be closer to the actual product. Explain.
2,400 gallons
What are the expression and partial products for the following equation: 26 x 19
20x10=200
6x10=60
20x9=180
9x6=54
Bags of potatoes weigh 35 pounds each. Cases of onions weigh 19 pounds each. Estimate which weighs more: 23 bags of potatoes or 32 cases of onions. Explain.
23 bags of potatoes
When multiplying a 2 digit by a 2 digit number
and one is a multiple of ten, what strategy can you use?
Multiply the basic fact and add a zero.
Miranda says that 30 x 26 is greater than 20 x 36. Is she correct? Explain.
Yes, because 780 is greater than 720
A store sells about 45 gadgets a day, 7 days a week. About how many gadgets might the store sell in 4 weeks? Explain how you can estimate and use partial products to find your answer mentally.
About 1,350 gadgets
Example: 45x7x4= about 45x30. 40x30=1200 and 5x30=150. 1200+15=1315
An average person in the United States eats 17 gallons of popcorn each year. How many gallons of popcorn does the average person eat in 12 years? Give a reasonable estimate as well. Is your estimate an overestimate or an underestimate?
204 gallons of popcorn
(Check estimates/over/under)
Rose visited 23 cities on her vacation. She bought 8 souvenirs in each city to send to her friends. Rose paid $3 in postage for each souvenir she sent. How much did Rose spend? Show your work.
$552
Example: 23x8x$3 = (23x3) x8 = 69x8 =$552
Draw an array using place value blocks to model 23x11. Find the product. Use an estimate to determine if your answer is reasonable.
Check array
253
25x10 = 250