Rounding numbers is a mathematical action that allows you to reduce the number of digits in a number, replacing it with an approximate value. The rounding of numbers is used for convenience in calculations.
After all, you do not want to get confused and hammer your head with numbers that have five digits after the comma, or even more. There are several rounding rules for numbers:
If the first digit you want to discard,Is greater than or equal to 5, then the last digit that remains is increased by one. Example: take the number 25.274 and round it to the tenth. The first discarded digit is 7, greater than 5, then the last stored digit - 2 is incremented by one. That is, a rounded number is obtained - 25.3.
If the first digit you are going toDiscard, less than 5, then the increase of the last saved digit does not occur. Example: 38,436 rounded to the tenth. The first digit that we want to discard is 3, less than 5, which means that the last digit saved - 4 does not increase. There remains a rounded number - 38.4.
If the number you want to discard is 5, butAfter it there are no significant digits, then the last stored digit remains unchanged, if it is even, and if it is odd, it increases by one. Example 1: there is a number 42.85, round it to the tenth. We drop the number 5, a, because After it there are no significant digits, and the last stored digit 8 is even, it remains unchanged. Ie, we get the number 42.8.
Example 2: the number 42,35 is rounded to the tenth. The discarded digit 5 does not have significant digits, but the last stored digit 3 is odd, it, accordingly, increases by one and becomes even. We get 42.4.