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+ - Decimals
Multiplication of Decimals
+ - Equations
Estimating
Decimal Word Problems
100

58.9 + 3.04 = 

61.94

100

.6 x 2.1 = 

1.26

100

3.2 + w = 7.1

Solve for w.

w = 3.9

100

3.73 x 8.16 = 

Use rounding to estimate each product.

4 x 8 = 32

100

Alan is connecting three garden hoses to make one longer hose. The green hose is 6.25 feet long, the orange hose is 5.755 feet long, and the black hose is 6.5 feet long. What is the total length of the hose?

18.505

200

.004 + 5.1 = 

5.104

200

4.25 x 21 = 

89.25

200

w - 5.8 = 18.2

Solve for w.

w = 24

200

8.498 x 5.602 =

Round to estimate each product.

8 x 6 = 48

200
The average length of a humpback whale is 13.7 meters. The average length of a killer whale is 6.85 meters. How much longer is the humpback whale than the killer whale?
6.85 meters
300

.9843 + 2.67 = 

3.6543

300

.03 x .03 = 

.0009

300
How can you solve the equation r + 21.5 = 39.5?


Isolate the variable by subtracting each side by 21.5

300

16.954 x 3.5 =

Use compatible numbers to estimate each product.

17 x 4 = 68

300
A pen costs $1.38. The sales tax is 0.06 of the cost. What is the amount of sales tax?
$0.08
400

.468 - .059 = 

.409

400

2.003 x .05 = 

.10015

400

x + 11.4 = 25

What do you have to do to isolate the variable?

Subtract both sides by 11.4.

400

55.93 x 8.34 =

Use compatible numbers to estimate each product.

60 x 8 = 480

400
A classified ad costs $2.45 per line per day. How much will it cost to run a 4-line ad for 7 days?
$68.60
500

5.45 - 3.799 = 

1.651

500

.312 x 1.67 = 

.52104

500

The equation is z - 28.2 = 44.4. Pat thinks the answer is 62.6. Explain why you agree or disagree. 

Pat is wrong because when you add 28.2 + 44.4 = 72.6 not 62.6.

500

Elena used rounding to estimate 7.864 x 3.29 = 24. Peter used rounding to estimate 7.864 x 3.29 = 32. Which student is correct? What mistake was made?

Elena is correct. 7.864 rounds to 8 and 3.29 rounds to 3, which means 8 x 3 = 24. Peter rounded 3.29 to 4. 

500
Ms. Blox bought 6 pounds of hamburger at $1.88 per pound and a bag of potatoes for $1.35. How much did she spend in all?
$12.63