Multiply Decimals by Powers of 10
0.62 x 10
6.2
Round each decimal to the nearest whole to estimate each product.
1.56 x 48
96
12 x 0.08
1.9 x 0.4
0.76
Anthony bikes a 16.2 mile long trail. If he bikes it 4 times, how far will he have traveled?
64.8
0.024 x 1,000
24
Round each decimal to the nearest whole then multiply.
147 x 10.4
1,470
1.75 x 4
7
5.6 x 0.8
4.48
A 100 watt solar panel usually costs $146. They are on sale for 0.65 of the regular price. Multiply $146 x 0.65 to find the sale price.
$94.90
19.212 x 102
1,921.2
Round each decimal to the nearest whole then multiply.
99.7 x 92
920
0.45 x 102
45
0.2 x 6.8
1.36
Tori wants to set up 14 small wind turbines with 3 blades each. If 6 wind turbine blades cost $64.25, how much will all the blades cost?
14 x 3 = 42
42/6 = 7
$64.25 x 7 = $449.75
10? x 12.35 = 12,350
103
Round each decimal to the nearest tenth then multiply.
23.71 x 4.76
113.76
3 x 2.89
8.67
9.1 x 0.3
2.73
A bag of grass seed weighs 6.9 pounds. How much would 2.5 bags weigh?
17.25
Choose all equations that are true when 103 is placed in the blank.
A. 4.2 = ____ x 0.042
B. 420 = ____ x 0.42
C. 4,200 = ____ x 4.2
D. 0.042 = _____ x 42.0
E. 42 = ____ x 0.042
B, C ,E
Some Native American tribes made jewlery with shells. If each shell is about 1.5 inches long. About how much longer would a necklace made with 24 shells be than a necklace made with 18 shells? Round to the nearest whole. Is your answer and overestimate or underestimate?
2 x 24= 48 (1.5 x 24 = 36)
2 x 18 = 36 (1.5 x 36 = 27)
48 -36 = 12 inches (36 - 27= 9); Overestimate
If 0.36 x 4 = 1.44, how would your product be different if the factors were 0.36 and 0.4?
The decimal would be one place over to the left because 0.4 is 1/10 the value of 4.
Explain why multiplying 37.4 x 0.1 gives a product that is less than 37.4.
0.1 or 1/10 is less than 1 whole. When you multiply 37.4 by a number less than 1 whole the product will be smaller than 37.4. (3.74 - move the decimal to the left 1 place to show 37.4 is 1/10 of 37.4))
Katie jogs from her house to the library and back again to tutor students. The distance from the house to the library is 0.28 mile. If Katie tutored at the library 328 days last year, about how many miles did she jog?
0.28 x 2 = 0.56 (0.30 x 2 = 0.60)
0.56 x 328 = 183.68 mi ( 0.60 x 300 = 180 mi)