Multiplication will never get easier than this, because in binary you will never multiply anything greater than 1!
011 Decimal: 3 * 110 * 6 --------- ------- 000 18 011 011 --------- 10010 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11010010 Decimal: 210 * 10010101 * 149 ------------- --------- 11010010 1890 00000000 840 11010010 210 00000000 --------- 11010010 31290 00000000 00000000 11010010 ----------------- 111101000111010 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You should notice the pattern above. When multiplying by a 0, it is zero across the board, when multiplying by 1, it is the same number it always is (the top number). This is important when we get into bitshifting. With a large enough register, we can just shift and add to multiply. For instance if we count one set of zeros, then a 1's row again we shift twice to the left then add, if we count two rows of zeros then a 1's row again, we shift 3 times to the left than add. You do not have to understand this right now. Really, if you understand multiplication in binary, then this page has done it's job so far. Hang with it!
Division is just as simple in binary notation becuase when you divide, your numbers may either go into the number, or not. In other words if the divisor goes into the number you are dividing, it will only go in once, or not at all. The only quotent you can have is either a 1 or a 0.
10002 ÷ 1002 = 102 ≡ 810 ÷ 410 = 210
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 ____________ 100 / 1000 100 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 10 ____________ 100 / 1000 100 ------------ 0000 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You just divide and subtract just like you would with the decimal system. Here is a larger example:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ____________ 1001 / 110110 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 ____________ 1001 / 110110 1001 ____________ 010010 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11 ____________ 1001 / 110110 1001 ____________ 010010 1001 ____________ 000000 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 110 ____________ 1001 / 110110 1001 ____________ 010010 1001 ____________ 000000 000000 ____________ 000000 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~