An unbiased coin is tossed thrice. Find the probability of the following event:
$C:$ at most $2$ heads are received. (in $/8$)

Two balanced dice are rolled simultaneously. Then,the probability that the sum of numbers on the dice is $7$ is ............

$A$ card is drawn at random from a well-shuffled pack of $52$ cards. The probability of that card being a jack is $\ldots \ldots \ldots$

$A$ balanced die is rolled once. Then,the probability that the number on the die is a prime number is .........

Three unbiased coins are tossed simultaneously. Then,the probability of receiving at least two heads is ..........

$A$ balanced die is rolled twice. Then,the probability that the sum of numbers received in two trials is $12$ or less than $12$ is ...........