You bought a cute little girl mouse at the pet store. This mouse can breed once every month, 7 babies at a time. So how many mice will you own in exactly twelve months?

“84”

This guess assumes that the mouse breeds every month without considering that you only have one mouse, which cannot breed alone.

“7”

This guess assumes that the mouse will breed only once in the year, producing one litter of 7 babies, but does not account for the fact that you need at least two mice to produce offspring.

“12”

This guess assumes that you will get one baby mouse per month, but it fails to recognize that you cannot have any breeding occurring with just one mouse.