Estimation
Estimate each product by rounding.
5.73 x 3.16
18
(5.73 rounds UP to 6 and 3.16 rounds DOWN to 3).
What is the product? Use patterns to solve.
A- 2.1 x 10 = ?
2.1 x 100 = ?
B- 3.03 x 10 = ?
3.03 x 100 = ?
A- 21
210
B- 30.3
303
1. 3.8 is _____ of 38.
2. 0.92 is _____ of 92.
1. 1/10
2. 1/100
Jason buys 0.9 pound of cabbage. The grocery store charges $0.60 per pound. How much will Jason pay for the cabbage?
.54 cents
.6 x .9 = .54
What is the product? Use an area model to solve.
32 x 1.5
48
Estimate each product by rounding.
7.44 x 4.21
28
(7.44 rounds DOWN to 7, and 4.21 rounds DOWN to 4).
If a bottle of laundry detergent weighs 2.1 kg, how much would 10 bottles weight?
21 kg.
2.1 x 10 = 21kg
Maya ships some test samples. She has 128 test samples that weigh 0.1 pound each. How many pounds will the samples weigh altogether?
12.8
128 x .10
What is the product?
1) 8 x 0.2 = ?
2) 0.4 x 0.8 = ?
1) 1.6
2) 0.32
The Mountaintop Ski Shop sold 15 pairs of gloves at $8.50. How much did the shop make? Use an area model.
15 x 8.5 = $127.50
Anna has $40 to spend on downloading music. If each song costs $1.29, does she have enough money to download 16 songs? Explain how you can use estimation to solve.
Yes. Even if $1.29 was rounded to $2, 16 x 2 is still under $40, which means she would have enough.
Pencils - $0.35 Notebooks - $1.25
Binder - 2.45
a. What is the cost of 100 pencils?
b. What is the cost of 10 notebooks?
c. What is the cost of 10 binders?
a. $35.00
b. $12.50
c. $24.50
Evelyn collected 69 dimes. The book she wants to buy is $7.50. Does she have enough money to buy it? Explain.
No.
69 x .10 = 6.90. The book costs $7.50. She does not have enough.
Trevor is buying a new desk. It is 1.5 m long and 0.5 meter wide. What is the area and perimeter of the desk?
A = 0.75 - 1.5 x .5 = 0.75
P= 4 m 1.5+1.5+0.5+0.5 = 4
What is the product? Use an area model to show your work.
7.4 x 1.2
8.88