Powers of 10
What is 8.04 × 101?
80.4
9.21 × 103 = 921
False! The correct product is 9,210
Which equation provides the best estimate of the product of 229 and 3.22?
This is the best estimate, because the estimated factors are closer to the original factors than the other equations.
Rounding to the nearest tenth, do you have an over estimate or an under estimate?
45.07 × 3.45
OVER!
What is the product 49 × 0.7?
34.3
There are 100 tiles that were purchased to raise money for a new playground. The tiles will be laid along a walkway. Each tile is 4.75 inches wide. If the tiles are going to all be lined next to each other, how many inches long will they cover along the walkway?
475
0.921 × 104 = 9,210
TRUE!
Jorge ordered 22 bottles of juice. Each bottle holds 6.32 ounces of juice.
Which is the best estimate of the number of ounces of juice Jorge ordered?
B. 120 ounces
6 x 20 = 120
Rounding to the nearest tenth, do you have an over estimate or an under estimate?
19.74 × 5.53
UNDER!
Brianne takes 4.75 minutes to bike around the block. How long does it take Brianne to bike 6 times around the block?
28.5 minutes
What is 0.738 × 104?
7,380
Rounding 92.543 to the nearest whole number is 92.000
False! Since there is a 5 in the tenths place and the wholes start at the ones place 92.5 is closer to 93 than 92. The answer is 93.
Which is the best estimate of 28 × 0.64?
30 x .5 = 15
15 is closest the the actual product of 17.92.
Rounding to the nearest tenth, do you have an over estimate or an under estimate?
8.16 × 60.29
OVER!
Charlotte buys 4 packs of gum. Each pack costs $1.19. What is the total amount Charlotte spends
for gum?
4 x $1.19 = $4.76
What is 4.346 x 103?
4,346
(5.37 x 103) > (53.7 x 102)
FALSE, the two expressions are equivalent!
What is the difference between rounding to estimate, and using compatible numbers to estimate?
Rounding has rules and consistent logic, but compatible numbers are simply chosen by the mathematician.
Rounding to the nearest tenth, do you have an over estimate or an under estimate?
2.92 × 77.81
UNDER!
A carton holds 42 erasers. Each eraser weighs 3.6 ounces. What is the total weight of the carton?
151.2 ounces
Leroy’s house is 14.5 feet tall. The Willis Tower in Chicago is 100 times as tall as Leroy’s house.
What is the difference in height between the Willis Tower and Leroy’s house?
Enter your answer in the box.
Willis Tower - Leroy's House = Diff in height
(14.5 x 100) - 14.5 = 1,435.5 feet
The Willis Tower is 1435.5 feet taller than Leroy's house.
(7 × 0.39) < (5 x .6)
TRUE! 2.73 < 3
Jackie drinks a bottle of water and a bottle of orange juice every morning. The bottle of water has 16.9 ounces. The bottle of orange juice has 15.2 ounces.
What is the best estimate for the total amount Jackie drinks in the morning for an entire week
and give a good explanation for that estimate?
About 210 ounces; She drinks about 17 + 15 = 32 ounces each morning.
There are 7 days in a week. 30 × 7 = 210.
Rounding to the nearest tenth, do you have an over estimate or an under estimate?
32.86 × 10.4
OVER!
6.2 × 0.04 = 2.48
Is the equation true? Explain.
The equation is false, because there are 3 digits in the two factors to the right of the decimal. The answer is .248, not 2.48.