(10^2)(2)+ (10^1)(3)+(10^0)(4) = 100*2 + 10*3 + 1*4 = 200 + 30 + 4 However, it the placeholder need not be 10 in general. The Binary System , for instance, uses only 0's and 1's (powers of 2). Here is the same number, 234, written in Binary: One Hundred Twenty Eight