Topic 1
There are 12 girls on Janelle's soccer team. Uniforms cost $33 each. Which equation uses ESTIMATION correctly to show ABOUT how much money the team spent?
12 rounds to 10
33 rounds to 30
10 x $30 = $300
There are 19 classes at Jerome Elementary. There are 24 students in each class. Write an expression that uses compatible numbers to ESTIMATE the number of students at Jerome Elementary.
19 rounds to 20
24 is compatible with 25
20 classes x 25 students = ABOUT 500 students
Mark's football team has scored about 25 points each game. They played 11 games this season. What is the best ESTIMATE for the total number of points they scored in the season?
25 is a compatible number
11 rounds to 10
25 x 10 = 250
ABOUT 250 points
In a science contest, 30 students will present their science projects. Each student gets to talk for 20 minutes. How much time is needed to present all of the science projects?
30 students x 20 minutes = 600 minutes in all
Trey is building 15 model boats. Each boat uses 20 pieces of balsa wood. How many pieces of balsa wood does Trey need in all?
15 model boats x 20 pieces of balsa wood =
300 pieces of balsa wood total
Mr. Garza bought paper cups for his food truck. Each package contained 70 cups. If he bought 10 packages, how many cups does he have total?
70 cups x 10 packages = 700 cups total
A baker uses 13 eggs in each batch of cookies. What is the best way to use compatible numbers to ESTIMATE the number of eggs the baker uses for 24 batches of cookies?
13 is compatible with 15 or 10
24 is compatible with 25
15 x 25 =
or 10 x 25 =
Miriam gets paid $23 each time she takes care of her neighbor’s children. She plans on caring for them once each week for the next 12 weeks. How much money will Miriam make?
$23 x 12 weeks = $276 in 12 weeks
400
60 x 30 =
1,800
50 x 15 =
750
60 x 21 =
1,260
Estimate 54 x 15 =
54 rounds to 50
15 rounds to 20
50 x 20 = 1,000
Estimate 11 x 68 =
11 rounds to 10
68 rounds to 70
10 x 70 = 700
Use compatible numbers to estimate 58 x 12 =
58 is closest to 60
12 is closest to 10
60 x 10 = 600
Use compatible numbers to estimate 76 x 39 =
76 is closest to 75
39 is closest to 40
75 x 40 = 3,000
OR
76 is closest to 80
39 is closest to 40
80 x 40 = 3,200
26 x 18 =
468
11 x 16 =
176
22 x 88 =
1,936
73 x 47 =
3,431
51 x 12 =
612
64 x 32 =
2,048
33 x 20 =
660
93 x 50 =
4,650
54 x 64 =
3,456