It’s important to pay particular attention to negative numbers, which do not work exactly the same way. In the case of a negative number, the last digit in this position remains unchanged if it is followed by a 0, 1, 2, 3, 4 or 5, or the digit is increased by 1 if it is immediately followed by a 6, 7, 8 or 9.
If rounding a decimal number to the nearest whole, then:
- 34.4 rounded gives 34
- 34.5 rounded gives 35
- 34.6 rounded gives 35
- −34.4 rounded gives −34
- −34.5 rounded gives −34
- −34.6 rounded gives −35
To solve some problem situations, the context determines how to round them. So, we may have to round them to the nearest greater whole number or to the nearest lesser whole number. This is known as rounding up or rounding down to an approximate value.
If we have to divide 30 bottles into cases that can each contain 12 bottles, then the result of the division of 30 by 12 will give 3, which is rounding up to an approximate value, if we are looking for the number of cases required, or 2 if we are looking for the number of cases that are filled completely.