In order to convert 110010101 into decimal I matched up each number starting with the first 1 on the farthest right with 2^0 then you move over to the left one number at a time and increase the power that 2 is raised to. For example, the last 1 on the right of that binary number is equal to 2^0 and the 0 that is to the left of that 1 is equal to 2^1. Then the 3rd number in from the right which is a 1, is equal to 2^2. The final conversion equaled 393. However the process of converting decimal to binary is a little different. You start by dividing the decimal by 2 and if there is no remainder then you write down a 0 for the binary. However, if there is a remainder then you write a 1 for the binary. As you start compiling the binary numbers you always tack on the most recent number on the left of the existing string. If there is a remainder and you've accounted for it by putting a 1 in the binary number, you leave the remainder off of the next calculation when you divide by 2. You continue this process of dividing the decimal by 2 until the quotient is 0. This final result of this decimal to binary conversion was 1000010001. The difference between a positional and non-positional number system is that a positional system has specific place values. It the kind of system we use in out society today. For example, the lowest place value is the rightmost position, and each position to the left has a higher place value. A non-positional number system, for example, may use groups of two kinds of wedges representing ones and tens.