What are the possible remainders when the $100^{th}$ power of an
integer is divided by $125$? To reduce the number of cases to be
checked, express the number as $5p+q $ where $p $ and $q $ are
integers and $q=1,2,3,4 $ and find the hundredth power using the
Binomial Theorem.
In turn 4 people throw away three nuts from a pile and hide a
quarter of the remainder finally leaving a multiple of 4 nuts. How
many nuts were at the start?