Four dice (six-faced) are rolled. The number of possible outcomes in which at least one die shows $2$ is

There are two children in a family. The probability that both of them are boys is

The probability of a non-leap year having $53$ Mondays is .........

$A$ and $B$ toss a coin alternatively,the first to show a head being the winner. If $A$ starts the game,the chance of his winning is

$A$ game consists of tossing a coin $3$ times and noting its outcome. $A$ boy wins the game if all tosses give the same outcome (i.e.,three heads or three tails) and loses the game otherwise. The probability that the boy loses the game is

Three coins are tossed. Describe two events which are mutually exclusive.