Estimation of Numbers

Estimation deals with studying numbers and statistical data together. For a better understanding of data, we often round off the data or put it in fractional or decimal values. Therefore, estimation of numbers helps us get a clear view of the data, which assists in generating future results.

Definition

To make calculations easier, we generally guess a number or assume a value. This guessing of a number is known as an estimation. As the word denotes, estimation means estimating or judging a numerical value.

In practical lives, estimation also deals with approximating the numbers for better accuracy. This can be done by rounding off the decimal values or picking up an assumed answer for better calculations. For example, we can take 0.67 instead of taking 0.66895432. With 0.67, it is easier to calculate and find the data results rather than using the long numerical value.

Calculate an estimate

We estimate physical quantities daily in our lives. For example, how much sugar we need to bring from the market, the vegetables cost if we get them beforehand from the grocery shop, etc. All these practical examples require the calculation of estimates.

Estimates can be roughly calculated as well. For example, if we need to find the cost of a project in civil construction, we estimate the number of raw materials required to construct the particular structure. Engineers also use estimation to find the overall cost for building the structure.

Not only construction, every machinery, labour, and household item require estimation to not overspend over a commodity. Therefore, the calculation of estimation is very necessary for our daily lives.

General rule of estimation

To estimate the numerical values, we need to do the following:

 1. We need to round off the numbers if the numeric value is too large for calculations.
 2. We can round off to the digits till we want. For example, 9.556644 can be rounded off to 9.6 or even 9.557, as per our requirements.
 3. We need to observe the digits that we need to round off and their place. If the end digits of any number belong between 0 and 4, the end digits will be retained. For example, consider the number 456.6784. In this, the last digit is 4.
 4. If we want to round off the last digit, we will remove 4 and retain the original value as 456.678. This way, our value has reduced, but the significance is the same.
 5. If the end digits of any number belong between 5 and 9, then we drop the number and increase the preceding number by 1. For example, consider the similar number 456.678. Here, we have already dropped 4. The end digit is 8 here. So we need to drop 8 and increase its preceding value, i.e. 7, by 1. Therefore, the result will be 456.68.
 6. We can further reduce the value to 456.7 using rule number 5.
 7. See how a big number 456.6784 reduced to 456.7.
 8. We could have directly done the same by knowing the place value we need to round off. For example, we need to round off just after the decimal in the number 456.6784. Here, the digits after 6 are greater than 5. Therefore, using rule number 5, we need to drop every number and increase the preceding number by 1. As a result, we get 456.7.