How to round numbers

Rounding numbers is a mathematical operation that allows to reduce the number of digits in the number, replacing it with the approximate value. Rounding numbers is used for convenience in the calculations. Don't want to get confused and bother with the numbers that are after the decimal point five digits or more. There are a few rules of rounding numbers:

Instruction

1. If the first digit that you want to discard greater than or equal to 5 then the last digit that remains is incremented. Example: take the number 25,274 and round it to tenths. First cast by figure 7, more than 5, then the last stored digit is 2 is incremented. Ie, it turns a round number was 25.3.
2. If the first digit that you are going to drop less than 5, increase the last stored digit does not occur. Example: 38,436 rounded to tenths. The first figure that we want to reject - 3, less than 5, then the last stored digit 4 is not increased. Remains rounded number of 38.4.
3. If the number you want to reject, is equal to 5, but it has no significant digits, then the last stored digit is unchanged if it is even and if is odd, then is incremented by one. Example 1: there are a number 42,85, round it to tenths. Reject figure 5, and, because it has no significant digits, and the last stored digit 8 is even, it remains unchanged. I.e., the resulting number is 42.8.
   
   Example 2: the number 42,35, rounded to tenths. Reject figure 5, does not bring about significant digits, but the last stored digit 3 is odd, it is, respectively, increases by one and becomes even. Get to 42.4.