So in the number 1.120, the number on the left side of the decimal is the whole number. the numbers on the right side of the decimal are called decimals. The first decimal is the tenth place. The number to the right of that is the hundredth place. The last number, the 0, is the thousandth place. You round up or down in the thousandth place. 5 or up goes to lets say 6 in the number 2.345. If it is 4 or lower, you round down so the number would stay the same.