Why does there have to be two numbers after the decimal?

Answer 1

There doesn't always have to be two numbers after the decimal. If you are asked to round to the nearest hundreth, then use two places after the decimal. If you are asked to round to the nearest thousandth, then use 3 places after the decimal. If you are asked to round to the nearest tenth, then use 1 place after the decimal. If you are not told where to round, then it is up to you. One common way of doing it is to use significant figures. In other words, if you are dividing two numbers to get a decimal; count the number of significant figures in the divisor and the dividend. Whichever one has the least number of significant figures, use that number of significant figures in your answer. For example: 30.5 / 1.3456789

30.5 has the least number of significant figures; so use 3 significant figures in your answer. Answer: 22.7 If you are working with money, then always use two numbers after the decimal. For example: Add $30.15 + $201.25 Answer: $231.40