How to Round numbers?
The process to round off numbers comprises several steps. Here are some rules that you need to use while rounding numbers.
1. The rule of less than 5 and 5 or greater than 5
The process of rounding uses “5” as the benchmark digit. If a number is less than 5, nothing is added to the number on its left and it is replaced by 0. Similarly, if the number is greater than 5, “1” is added to the number on the left.
2. Check the unit to which the rounding has to be done
This is an important area in which the user has to be checked. If there is a number “4255”, and it has to be rounded off to the nearest 10, only the 5 on the extreme right would be dropped and 1 would be added to the 5 on its left. For instance, if you consider the 4255, it would be 4260 when rounded off to the nearest tenth. Similarly, if it has to be rounded off to the nearest hundred, it would be 4300.
Rounding to the nearest tenth
Consider that we have the number 4876 and it has to be rounded off to the nearest 1000. Here are the steps which you have to complete.
The number on the extreme right is 6. In accordance with the rules, it is more than 5. Thus, add “1” to the number on its right which is “7” in this case. Thus, the number 4876 rounded off to the nearest tenth would be 4880.
Rounding to the nearest hundred
Consider that we have the number 5776 and it has to be rounded off to the nearest 100. Let us check the steps which have to be completed by the user.
- You need to start by rounding the number to tenth. The number on the extreme right is 6. According to the regulations of rounding, it is greater than 5. The number on the left of 6 is 7 so 1 would be added to it. Hence, the number 5776 would become 5780.
- Once you have rounded off the number to tenth, initiate the process to round it off to a hundred. In the number, 5780, the required digit is 8. As this digit is greater than 5, 1 will be added to the number on its left. In this case, this number is 7. Thus, when 5780 will be rounded off to the nearest hundred, it would be 5800.
Rounding to the nearest thousand
Which steps would be executed if you wish to round off? Let us perform this rounding the process for a number 6354
- The first step is rounding the number to ten. The first digit is 4. As it is less than 5, it would be dropped without adding anything. A zero would be written in its place. Hence, when the number is rounded off to ten, the number would be 6350.
- To round off to a hundred, the number 5 would be removed and 1 would be added to 3. Thus, after rounding, the number would be 6400.
- To round off to thousand, 4 will be removed as it is less than 5 and a zero would be written in its place. The number, when rounded off to thousand, will be 6000.
Rounding in decimals and significant numbers
When you talk about rounding decimals, you need to understand the rules of significant figures. For instance, if the number 0.4556 has to be rounded off to 3 significant figures, the rounding would involve specific regulations.
Here are the rules which you need to use for significant figures.
1. All non-zero numbers are significant
This simply means that any number greater than zero would be counted as significant. If you have the number 0.4521, it would have four significant numbers. If you have to round it off to 3 significant digits, the 1 on the extreme right will be dropped as it is less than 5. Hence, 0.4521 rounded off to three significant digits will be 0.452.
2. The zero between two non-zero numbers will be counted as significant
This is an important point which users would be well aware of. If you have the number 0.452, the number of significant numbers is 3. Similarly, the number 0.4025 has four significant digits. Here, the zero between 4 and 2 is counted as a significant digit because it is present between two non-zero numbers.