ümardusreegleid

Umardusreegleid, or rounding rules, are a set of conventions used to approximate numbers to a desired degree of precision. The most common method is rounding to the nearest specified place value. When the digit to the right of the desired place value is five or greater, the digit in the desired place value is increased by one, and all digits to its right are replaced with zeros. If the digit to the right is less than five, the digit in the desired place value remains the same, and all digits to its right are replaced with zeros.

There are variations to this rule, particularly concerning the handling of the digit five. "Round half up" is the most widely taught method. Another common method is "round half to even," also known as banker's rounding. In this method, if the digit to the right of the target place is five, the digit in the target place is rounded to the nearest even digit. This approach is often used in scientific and financial contexts to minimize cumulative rounding errors.

Rounding can be applied to integers, decimals, and even fractions. For example, rounding 3.14159 to two decimal places using "round half up" would result in 3.14. Rounding 3.14659 to two decimal places would yield 3.15. When rounding to a whole number, 7.8 rounds to 8, while 7.3 rounds to 7. The specific rule to be used is often dictated by the context or explicitly stated. Understanding rounding rules is fundamental in mathematics, science, and everyday calculations.