The probability of getting the number $7$ while throwing a balanced die once is ...........

In a packet of $500$ screws,$80$ screws are defective. Find the probability that a screw selected at random from the packet is non-defective. (in $/25$)

Chits numbered from $1$ to $120$ are put in a box and a chit is drawn randomly from the box. The probability that the chit drawn bears a $3$-digit number is ............

The probability of scoring $100$ marks in a question paper of $100$ marks is ................

$A$ balanced die is rolled twice. Then,the probability of the event that the sum of the numbers received in two trials is more than $10$ is ...........

$12$ defective ballpens are mixed with $132$ non-defective ballpens. They all look alike. $A$ ballpen is selected at random from that lot. Find the probability that a defective ballpen is selected.