Estimation in Real Life

For instance, if you were to make a quick budget on transportation to a place to and from and the cost of a trip is £5.7, surely, you would make a budget of £12. By approximating or rounding up 5.7 to 6 and multiplying by 2.

For instance, if you were to make a report on the number of people leaving Frimley in a discussion, the exact population is 6178. It would be easier to say, "About 6,000 people leave in Frimley".

Note that there was no operation involving addition, subtraction, multiplication, or division before you made your estimate.

For example, 500 is an estimate of 483. Similarly, 600 is an estimate of the product between 3.8 and 148.

For example, if the population of a place is 697, the exact value is 697 but the estimate is 700.

Likewise, when calculating the product between 3.8 and 148, the exact value is 562.4 but its estimated value could be 600.

For instance, if you were to add 2345 to 3211 and use a calculator you arrived at 2556. Surely, by your estimate, you should be getting something above 4000.

Because you are aware of that, you would then check your calculator and notice that rather than typing 3211, you typed 211. Without having an estimate beforehand, it would be had to spot errors.

For instance, Finicky built a house in 2009 for £250,000. If Kohe, his son, wishes to build the same house 3 years after, he would have to make an estimate of about £300,000 per peradventure because there are other factors that may increase his expenditure on the house.

This stands to be the reason why estimations are generally used in the business world.

For example, 56 784 can be approximated to 60 000 which is the highest place value, or 57 000 which is the next highest place value. This is advisable because it is easier to find the product between 60 000 and 3 than 56 880 and 3.

For example, in 56317, you wish to estimate to the nearest thousand, then 6 is your main digit and the next number to the right after 6 is 3 but it is less than 5. So my estimate becomes 56000.

For example, in 56317, you wish to estimate to the nearest ten thousand, then 5 is your main digit and the next number to the right after 5 is 6 which is greater than 5. So my estimate becomes 60000.

Ireti is a news reporter and she wishes to give an estimate of the following populations to the nearest thousand,

a) Reading - 347,510

b) Aldershot - 37,131

c) Farnborough - 65,034

Solution

If you apply the earlier explained rules, your answer for this task would be,

a) Reading - 348,000.

This is because the digit occupying the thousand position is 7 and the digit in the next lower place value (hundred) is 5. Remember that the digit in the next lower place value needs to be equal to or greater than 5 to round up the next digit. This is why 7 is rounded up to 8. So the population of Reading is approximated to 348,000.

b) Aldershot - 37,000.

This is because the digit occupying the thousand position is 7 and the digit in the next lower place value (hundred) is 1. Remember that the digit in the next lower place value needs to be equal to or greater than 5 to round up the next digit. This is why 7 is not rounded up to 8. So the population of Aldershot is approximated to 37,000.

c) Farnborough - 65,000

This is because the digit occupying the thousand position is 5 and the digit in the next lower place value (hundred) is 0. Remember that the digit in the next lower place value needs to be equal or greater than 5 to round up the next digit. This is why 5 is not rounded up to 6. So the population of Aldershot is approximated to 65,000.

Find to the nearest thousand cubic meters, the volume of a cuboidal tank measuring 63m by 28m by 11m.

Solution

We recall that the volume of a cuboid is given by

$Volume=length\times breadth\times height$

In this question, neither the length, breadth nor height was specified, and looking at the formula, the specification does not really matter. So we use an estimate of each dimension to get our volume in the nearest thousand cubic meters.

Thus, we can approximate the length, breadth and the height to

$$\begin{gathered} 63m\approx 60m \\ 28m\approx 30m \\ 11m\approx 10m \end{gathered}$$

And thus the volume will be approximated to,

$$\begin{gathered} Volume\approx 60m\times 30m\times 10m \\ Volume\approx 18000m^3 \end{gathered}$$