The decimal system is said to be based on powers of 10, since, as we have seen, we can think of the digits in an ordinary decimal number as the coefficients of the powers of 10 in the expanded form of the number. These coefficients tell us how many times each power of the base number, 10, is to be added into the sum.
Now, is there anything in the whole wide world that prevents our basing a number system on powers of some number other than 10?