The numbering system used in most of the linear world. Where numbers are presented in exponential units of 10 and the position of the digit is quite significant. When we write “5,” we mean 5 units of 1 each. But when we write “5243,” we mean 5 units of 1000 (10x10x10) each, 2 units of 100 (10x10) each, 4 of 10 each, and 3 of 1 each.