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

$A$ coin is tossed two times. Find the probability of getting at most one head.

Two balanced dice are rolled. Find the probability that the numbers on two dice are equal.

There are $1000$ sealed envelopes in a box,$10$ of them contain a cash prize of $Rs. 100$ each,$100$ of them contain a cash prize of $Rs. 50$ each,$200$ of them contain a cash prize of $Rs. 10$ each,and the rest do not contain any cash prize. If they are well shuffled and an envelope is picked out,what is the probability that it contains no cash prize?

If you toss a coin $6$ times and it comes down heads on each occasion,can you say that the probability of getting a head is $1$? Give reasons.

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