**Positional notation** (or **place-value notation**, or **positional numeral system**) denotes usually the extension to any base of the Hindu–Arabic numeral system (or decimal system). More generally, a positional system is a numeral system in which the contribution of a digit to the value of a number is the product of the value of the digit by a factor determined by the *position of the digit*. In early numeral systems, such as Roman numerals, a digit has only one value: I means one, X means ten and C a hundred (however, the value may be negated if placed before another digit). In modern positional systems, such as the decimal system, the *position* of the digit means that its value must be multiplied by some value: in 555, the three identical symbols represent five hundreds, five tens, and five units, respectively, due to their different *positions* in the digit string. wikipedia

**Rounding** means replacing a number with an approximate value that has a shorter, simpler, or more explicit representation. For example, replacing $23.4476 with $23.45, the fraction 312/937 with 1/3, or the expression √2 with 1.414. wikipedia

*More premium learning materials at Education PH, your reliable partner for learning and success. Sa halagang P499/year, makakadownload ka na ng mga premium learning materials para sa iyong anak o estudyante.*