we can make it simple from an example like if we toss a coin we can get 2 possible outcome

if

we toss 2 coin we can get 2 * 2 possible outcome

if we toss 3 coin we can get 2* 2 *2 possible outcomes

so tossing a dice 6 times is same as tossing 6 dice one time.

for one fair dice the possible no of outcome is 6 {1,2,3,4,5,6}

for 2 dice possible outcomes 6*6

for 3 dice possible outcomes 6*6 *6

for 4 dice possible outcomes 6*6*6*6

for 5 dice possible outcomes 6*6*6*6*6

for 6 dice possible outcomes 6*6*6*6*6*6 = 6 ^6 [answer]