Page 317 - Basic College Mathematics with Early Integers

294 C HAPTE R 4 I DECIMALS

Solution:

1. UNDERSTAND. Read and reread the problem. Since we want to know “how
much greater,” we subtract.
2. TRANSLATE.

Denmark’s U.S.
How much
In words: is average minus average
greater
height height
T T T T T
How much
Translate: = 72.2 - 70.8
greater
3. SOLVE:We estimate by rounding each number to the nearest whole.
1 12
7 2 . 2 rounds to 72
- 7 0 . 8 rounds to 71
1 . 4 Exact 1 Estimate
4. INTERPRET. Check your work. Since our estimate is close to our exact
answer, 1.4 inches is reasonable. State your conclusion: The average height in
Denmark is 1.4 inches greater than the average U.S. height.
Work Practice 13

Calculator Explorations Decimals

Entering Decimal Numbers The display will read 4.335 . (Although entering
To enter a decimal number, find the key marked # . 8.625, for example, requires pressing more than one key,
To enter the number 2.56, for example, press the keys we group numbers together here for easier reading.)
2 # 56 .
Use a calculator to perform each indicated operation.
The display will read 2.56 .
1. 315.782 + 12.96 2. 29.68 + 85.902
Operations on Decimal Numbers 3. 6.249 - 1.0076 4. 5.238 - 0.682
Operations on decimal numbers are performed in the 5. 12.555 6. 47.006
same way as operations on whole or signed numbers. 224.987 0.17
For example, to find 8.625 - 4.29, press the keys 5.2 313.259
8.625 - 4.29 = or ENTER . + 622.65 + 139.088

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