趣味的数学-131
(3^1001)*(7^1002)*(13^1003)的个位数是多少?
【AHSME】
是了
9
(3^1001)*(7^1002)*(13^1003) =
(3*7*13)^1000 * 3 * 7^2 * 13^3 =
(xxxx3)^1000 * 3*49* *(xxx7) =
(xxxx9)^500 * (xxxx9) = (xxxx1)^250 * (xxxx9) =
xxxxx9