In the last notation, parentheses are the concise notation for the ± notation. For example, applying 10 1 ⁄ 2 meters in a scientific or engineering application, it could be written 10.5 m or 10.50 m, by convention meaning accurate to within one tenth of a meter, or one hundredth. The precision is symmetric around the last digit. In this case it's half a tenth up and half a tenth down, so 10.5 means between 10.45 and 10.55. Thus it is understood that 10.5 means 10.5 ± 0.05, and 10.50 means 10.50 ± 0.005, also written 10.50(5) and 10.500(5) respectively. But if the accuracy is within two tenths, the uncertainty is ± one tenth, and it is required to be explicit: 10.5 ± 0.1 and 10.50 ± 0.01 or 10.5(1) and 10.50(1). The numbers in parentheses apply to the numeral left of themselves, and are not part of that number, but part of a notation of uncertainty. They apply to the least significant digits. For instance, 1.007 94 (7) stands for 1.007 94 ± 0.000 07, while 1.007 94 (72) stands for 1.007 94 ± 0.000 72. This concise notation is used for example by IUPAC in stating the atomic mass of elements.