At a toy shop,there are $10$ toys in a box of which $3$ toys are defective. $A$ customer would purchase a non-defective toy only. The probability that a toy selected at random from the box is purchased by the customer is ..............

$A$ game of chance consists of spinning an arrow which comes to rest pointing at one of the numbers $1, 2, 3, 4, 5, 6, 7, 8$ (see figure),and these are equally likely outcomes. What is the probability that it will point at:
$(i)$ $8?$
$(ii)$ an odd number?
$(iii)$ a number greater than $2?$
$(iv)$ a number less than $9?$

Two unbiased dice are thrown once. Write all the possible outcomes of this experiment. What is the probability that the sum of numbers on two dice is $4$?

The probability of the month of April in any year having $5$ Sundays is ......... (in $/7$)

Chits numbered from $1$ to $100$ are put in a box and a chit is drawn randomly from the box. The probability that the chit drawn bears a $2$-digit number is ............

$A$ balanced die is rolled twice. Then,the probability of the sum of numbers received in these two trials being even is ...........