Rounding numbers

In this publication, we will consider what the rounding of a number is, according to what rules it is performed, and also analyze a practical example on this topic.

Content

What is number rounding

During the execution of certain calculations, it is quite often necessary to round the result obtained or use rounded values ​​in calculations.

rounding – this is the replacement of a number with a value approximate to it, let’s say, “reduced” to a certain number or sign.

Natural numbers can be rounded up to any (tens, hundreds, thousands, etc.) – it all depends on the original value and the required accuracy.

The number obtained as a result of rounding is called rounded or approximate.

There is a special symbol for rounding – followed by a rounded number. Pronounced like “approximately equal”.

Rounding rules

  1. We note the figure located in the category to which you want to round off.
  2. We separate all the numbers to the right of the selected section.
  3. Then there are two options:
    • if the numbers 0, 1, 2, 3 or 4 are to the right of the marked digit, then instead of all the digits separated to the right, we write zero. The digit itself remains the same.
    • if the numbers 5, 6, 7, 8 or 9 are to the right of the selected digit, then we also change all the separated digits to zeros, and add one to the digit itself.

Note: We discussed the rounding of decimal fractions in detail in a separate one.

A practical example

Let’s round the number 654 to the nearest thousand.

Decision:

Guided by the rules above, we mark the desired category and separate the numbers on the right from it with a vertical line.

Rounding numbers 

After the rounded digit is the number 7, therefore, we add one to the thousands digit (4 + 1), and change the numbers marked in red to zero.

Thus, we get: 654 ≈ 719.

This is the same number, rounded up to:

  • hundreds: ≈ 655 700
  • tens: ≈ 655 720

Note: rounded results are usually written without zeros, and an abbreviation corresponding to the rounding accuracy is necessarily added to them: “court”, “thousand”, “million” etc. For example, 126 ≈ 415 thousand

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