Ncert solutions mathematics class 8 Solutions for Chapter 16 playing with numbers

Exercises in Chapter 16 playing with numbers Grade 8

Exercise 16.1

Exercise 16.2

Questions in Exercise 16.1

Q1) Find the values of the letters in each of the following and give reasons for the steps involved.

Find the values of the letters and give reasons for the steps involved.

Q2)

Find the values of the letters and give reasons for the steps involved.

Q3)

Find the values of the letters and give reasons for the steps involved.

Q4)

Q5)

Find the values of the letters and give reasons for the steps involved.

Q6)

Q7)

Find the values of the letters and give reasons for the steps involved.

Q8)

Q9)

Find the values of the letters and give reasons for the steps involved.

Q10)

Questions in Exercise 16.2

Q1) If 21y5 is a multiple of 9, where y is a digit, what is the value of y?

If 21y5 is a multiple of 9, where y is a digit, what is the value of y?

Q2) If 31z5 is a multiple of 9, where z is a digit, what is the value of z? You will find that there are two answers for the last problem. Why is this so?

If 31z5 is a multiple of 9, where z is a digit, what is the value of z? You will find that

there are two answers to the last problem. Why is this so?

Q3) If 24x is a multiple of 3, where x is a digit, what is the value of x? (Since 24x is a multiple of 3, its sum of digits 6 + x is a multiple of 3; so 6 + x is one of these numbers: 0, 3, 6, 9, 12, 15, 18, ... . But since x is a digit, it can only be that 6 + x = 6 or 9 or 12 or 15. Therefore, x = 0 or 3 or 6 or 9. Thus, x can have any of four different values.)

If 24x is a multiple of 3, where x is a digit, what is the value of x?

(Since 24x is a multiple of 3, its sum of digits 6 + x is a multiple of 3; so 6 + x is one of

these numbers: 0, 3, 6, 9, 12, 15, 18, .... But since x is a digit, it can only be that 6 + x = 6

or 9 or 12 or 15. Therefore, x = 0 or 3 or 6 or 9. Thus, x can have any of four different

values.)

If 31z5 is a multiple of 3, where z is a digit, what might be the values of z?

Q4) If 31z5 is a multiple of 3, where z is a digit, what might be the values of z?