Show:
Using Mental Math
Estimating Products
Multiplying 2-Digit Numbers by Multiples of 10
Multiplying 2-Digit by 2-Digit Numbers
Problem Solving: Two-Question Problems! :)
100
25 x 10
250
100
Use rounding to solve: 42 x 73 =
40 x 70 = 2,800
100
20 x 51 =
1,020
100
41 x 23 =
943
100
Riley buys a sandwich for $4, an apple for $1, and a drink for $2. How much did she pay altogether? How much change would she receive if she paid with a $20 bill?
She paid $7 for her lunch. She got $13 back because $20 - $7 = $13.
200
80 x 500 =
40,000
200
Use rounding to solve: 602 x 43 =
600 x 40 = 24,000
200
32 x 30 =
960
200
12 x 27 =
324
200
Eric and Dominic mow their neighbors' lawns in the summer. Eric mows 5 lawns each week. Dominic mows three times as many lawns as Eric. How many lawns does Dominic mow each week?
5 lawns x 3 = 15 lawns
300
50 x 1,000 =
50,000
300
Use rounding to solve: 327 x 18 =
300 x 20 = 6,000
300
88 x 30 =
2,640
300
42 x 18 =
756
300
Dominic gets paid $20 for each lawn he mows. So does Eric. How much money did they get paid altogether after one week of working? (Hint: remember that Eric mowed 5 lawns and Dominic mowed 3 times as many)
Eric got $100 because 5 x $20 = $100. Dominic got $300 because 15 x $20 = $300
400
25 x 400 =
10,000
400
Estimate to decide which has a greater product, 39 x 21 or 32 x 32. Explain.
39 x 21 is about 40 x 20, which is 800. 32 x 32 is about 30 x 30, which is 900. Therefore, 32 x 32 is greater.
400
52 x 50 =
2,600
400
63 x 31 =
1,953
400
Taylor's mom brought 3 bags of popcorn and 3 bottles of water to the park. How many bags of popcorn and bottles of water did Taylor's mom take to the park?
3 + 3 = 6 bags and bottles
500
There are 9 players on each 4th grade basketball team in the Dublin City Schools league. What is the total number of players in the league if there are 30 teams? Use pictures, numbers, or words to show your answer.
9 x 30 = 270 players I multiplied the number of players by the number of teams to get the total number of players in the Dublin City Schools league.
500
A wind farm generates 330 kilowatts of electricity each day. About how many kilowatts does the wind farm produce in a week? Explain your answer using pictures, numbers or words.
330 rounds to 300 and there are 7 days in a week, so 7 x 300 = 2,100. Therefore, the wind farm produces ABOUT 2,100 kilowatts in one week.
500
Shivani and Lisa work as teacher assistants at Ohio State University. They earn $20 an hour! How much do they make altogether if they work 32 hours? Use pictures, numbers or words to explain your answer.
$20 x 32 hours = $640 per person. Since there are two people we need to double (or multiply by 2) $640. That equals $1,280. Therefore, they made $1,280 altogether.
500
A carton holds 24 bottles of juice. How many juice bottles are in 15 cartons?
24 x 15 = 360 bottles of juice
500
Each bag of popcorn that Taylor's mom brought to the park contained 16 servings. How many servings of popcorn did Taylor's mom bring to the park?
16 x 3 = 48 servings