### 1.2 Rounding & Calculators

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• 19. Estimating the Reasonableness of a Receipt

Use rounding to decide whether the total is reasonable. Explain your reasoning.

• Worked-Out Solution

Estimate each dollar amount by rounding to the nearest whole dollar.

The sum of the estimates is \$31. So, the grocery bill total is reasonable

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```  ______     ___     _    _      ___     _____
/_   _//   / _ \\  | || | ||   / _ \\  |  __ \\
| ||    / //\ \\ | || | ||  | / \ || | |  \ ||
_| ||   |  ___  ||| \\_/ ||  | \_/ || | |__/ ||
/__//    |_||  |_|| \____//    \___//  |_____//
`--`     `-`   `-`   `---`     `---`    -----`

```
• 20. Estimating the Reasonableness of a Receipt

Use rounding to decide whether the total is reasonable. Explain your reasoning.

These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.

``` _____      ______    _  __     ___    __    __
|  __ \\   /_   _//  | |/ //   / _ \\  \ \\ / //
| |  \ ||   -| ||-   | ' //   / //\ \\  \ \/ //
| |__/ ||   _| ||_   | . \\  |  ___  ||  \  //
|_____//   /_____//  |_|\_\\ |_||  |_||   \//
-----`    `-----`   `-` --` `-`   `-`     `

```
• 21. Estimating a Distance on a Map

Estimate the distance from Cheyenne to Gillette.

• Worked-Out Solution

Using the scale on the map, the distance is about 220 miles from Cheyenne to Gillette. However, when you check the distance with an Internet map site, you see it is actually 250 miles.

What you can learn from this is that the driving distance on a road (that curves) can be significantly greater than the straight-line distance "as the crow flies." In this particular case, the driving distance is about 14% more than the straight-line distance.

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```  ______    ______    ______     ___     _    _
/_   _//  /_   _//  /_____//   / _ \\  | \  / ||
| ||     -| ||-   `____ `   | / \ || |  \/  ||
_| ||     _| ||_   /___//    | \_/ || | .  . ||
/__//     /_____//  `__ `      \___//  |_|\/|_||
`--`      `-----`   /_//       `---`   `-`  `-`
`-`
```
• 22. Estimating a Distance on a Map

You are planning a trip from Riverton to Gillette. You want to stop in Douglas along the way. Estimate the total distance of the trip.

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``` __   _     ______    _____      ___
| || | ||  /_   _//  /  ___||   / _ \\    ____
| '--' ||   -| ||-  | // __    | / \ ||  |    \\
| .--. ||   _| ||_  | \\_\ ||  | \_/ ||  | [] ||
|_|| |_||  /_____//  \____//    \___//   |  __//
`-`  `-`   `-----`    `---`     `---`    |_|`-`
`-`
```
• 23. Estimating Fuel Cost for a Trip

Your car can travel 274 miles on a tank of gas. Each tank contains 12.7 gallons. Estimate the fuel cost for a trip from Laramie to Evanston City. Use a gas price of \$2.92 per gallon.

• Worked-Out Solution

Using the scale on the map, it looks like it is about 280 miles from Laramie to Evanston. Just to be safe, let's say it is 310 miles.

To find your gas mileage, divide 274 miles by 12.7 gallons.

To find the number of gallons you will use on the trip, divide the distance by the gas mileage.

Finally, to estimate the fuel cost of the trip, multiply the number of gallons by the price per gallon.

You can estimate that your fuel cost for the trip will be about \$42.

These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.

``` _    _     ______    ____       ___      ____
| \  / ||  /_   _//  |  _ \\    / _ \\   |  _ \\
|  \/  ||   -| ||-   | |_| ||  / //\ \\  | |_| ||
| .  . ||   _| ||_   | .  //  |  ___  || | .  //
|_|\/|_||  /_____//  |_|\_\\  |_||  |_|| |_|\_\\
`-`  `-`   `-----`   `-` --`  `-`   `-`  `-` --`

```
• 24. Estimating Area from a Map

Estimate the area of the portion of Yellowstone National Park that is in Wyoming.

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```  ______     ___     __   _     ______     _____
/_   _//   / _ \\  | || | ||  /_   _//   / ___//
| ||    / //\ \\ | '--' ||   -| ||-    \___ \\
_| ||   |  ___  ||| .--. ||   _| ||_    /    //
/__//    |_||  |_|||_|| |_||  /_____//  /____//
`--`     `-`   `-` `-`  `-`   `-----`  `-----`

```
• 25. Estimating Distances Between Two Cities

Describe different ways to find the distance between two cities.

• Worked-Out Solution

There are four basic ways to estimate distances for a trip.

• Obtain a printed map and use the scale to estimate the distance.

• Use a mapping service on the Internet. Three popular sites are

• www.RandMcNally.com
• www.MapQuest.com

• If you are in one of the cities, then you can enter the other city into a GPS system to find the distance to the other city.

• If you belong to a motor club, such as AAA, GM Motor Club, or Allstate, then you can ask the service to create detailed driving directions and maps for you.

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