Rounding Estimation and Measurement Rounding Some quantities

Rounding, Estimation, and Measurement Rounding Some quantities arc exact, like the number of people in a room, while others are approximations. An approximation is a number that is close to the exact value, but has fewer non-zero digits. More zeros makes it easier to work with. We round a number to a less accurate but simpler approximate value to make it easier to work with, while keeping most of the important information about the number. For example, if we learned that the U.S. trade deficit in June 2005 was exist58, 753, 421, 989, we probably could analyze how this was important to our lives just as well if it was rounded to exist59,000,000,000. In fact, without all of the non-zero digits, we could even write this number as a \"word-number\" hybrid by writing, \"exist59 billion\". It is usually a good idea to round a number like this, and if you listen to financial news reports, you will notice that the media often rounds numbers. For another example, if we wanted to measure the length of a window so that we could buy the right size replacement, we could use a very accurate measuring device and find that the length is 75.18952 cm. The window store is probably satisfied with the rounded version, 75 cm. But, the window is approximately 75 cm. For the following numbers, state whether it seems reasonable that the given value is exact or an approximation. Give a reason for your answer. 1. Measurement of the distance you drive from SF to LA is 420 miles. 2. Jenisa calculated her share of the lunch that she had with her high school friends yesterday and the figure was exist12.315. 3. The family\'s rent each month was exist1225. 4 The same family\'s monthly budget for food was exist840. 5. A group of friends calculated their share of the cost of a ski trip and the figure was exist342. For the following numbers, discuss how accurate each measurement needs to be for it to be useful, and why it requires that amount of accuracy. Also use phrases like \"at least\" or \"at most\" or \"to the nearest\" if appropriate for the situation. 1. Measurement for rope to tie down a load. 2. Measurement for wood in making a picture frame. 3. A cup of flour to make a cake. 4. Measurement of the length of die glass used to make the windows for a new building. 5. Scores used to compute your grade. 6. The amount of line to let out in a cast while fishing. 7. The time it will take to drive to a dinner party. 8. The amount of salt used in a pot of soup.

Solution

3.1.1]

Here we have to find valua is exact or an approximation.

1) $420 is exact value

2) $12,345 needs approximation

$12,345 can be written as 12,350

3) $1225 is exact value

4) $342 needs approximation.

$342 can be approximate as 340