Example of decimal system of numeration?

Answer 1

Hindu-Arabic numerals are an example of a decimal system (base-10). It is the same system we use to this day, albeit with Latin symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. It is a positional system, such that each column represents an increasing power of 10, from the rightmost column, which is 100. Columns to the right of the decimal point (if one is given) represent decreasing powers of 10, beginning with 10-1.

Thus, a number represented by the symbols 123.456 represents 1x102 + 2x101 + 3x100 + 4x10-1 + 5x10-2 + 6x10-3. This is read as literally meaning the number "one hundred and twenty and three and four tenths and five hundredths and six thousandths", which we usually shorten to "one hundred and twenty three point four five six".