Rounding
Rounding is the process of reducing the number of significant digits in a number. The result of rounding is a "shorter" number having fewer nonzero digits yet similar in magnitude. The result is less precise but easier to use.
For example: 53 rounded to the nearest tenth is 50, because 53 is closer to 50 than to 60.
Methodology
 Decide which is the last digit (e.g., tenths, hundredths) to keep
 Increase it by 1 if the next digit is 5 or more (known as rounding up)
 Leave it the same if the next digit is 4 or less (known as rounding down)
Examples:
 81.042 rounded to hundredths is 81.04 (because the next digit, 2, is less than 5)
 363.045 rounded to hundredths is 363.05 (because the next digit, 5, is 5 or more)

2.0437 rounded to hundredths is 2.04 (because the next digit, 3, is less than 5)
For negative numbers the absolute value is rounded.
Examples:
 −31.1349 rounded to hundredths is −31.13

−5.1350 rounded to hundredths is −5.14