Think about it like this: How many ways could you buy a single donut?....since there are 26 kinds, there would be 26 ways to buy. Now, if we could buy two...then we could buy each one 26 different ways, thus we could buy the two donuts 26*26 different ways. Each time you add another donut to the amount being bought, you multiply by another 26...thus, there would be 26*26*26*26*26*26*26*26*26*26*26*26....or 26^12 (fyi, this equals 95,428,956,661,682,200...yes, that's quadrillions...)