Playing with Numbers - Solutions 1

CBSE Class –VIII Mathematics
NCERT Solutions
CHAPTER - 16
Playing with Numbers (Ex. 16.1)

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

Ans. On putting A = 1, 2, 3, 4, 5, 6, 7 and so on and we get, 7 + 5 = 12 in which ones place is 2.

A = 7

And putting 2 and carry over 1, we get

B = 6

Hence A = 7 and B = 6

Ans. On putting A = 1, 2, 3, 4, 5, 6, 7 and so on and we get,8 + 5 = 13 in which ones place is 3.

A = 5

And putting 3 and carry over 1, we get

B = 4 and C = 1

Hence A = 5, B = 4 and C = 1

Ans. On putting A = 1, 2, 3, 4, 5, 6, 7 and so on and we get, A x A = 6 x 6 = 36 in which ones place is 6.

A = 6

Hence A = 6

Ans. Here, we observe that B = 5

so that 7 + 5 = 12.
Putting 2 at ones place and carry over 1 and A = 2, we get
2 + 3 + 1 = 6

Hence A = 2 and B = 5

Ans. Here on putting B = 0,

we get 0

3 = 0.

And A = 5, then 5

3 = 15

A = 5 and C = 1

Hence A = 5, B = 0 and C = 1

Ans. On putting B = 0, we get 0 , and A = 5, then 5

5 = 25

A = 5, C = 2

Hence A = 5, B = 0 and C = 2

Ans. Here product of B and 6 must be same as ones place digit as B.

1 = 6, 6

2 = 12, 6

3 = 18,
6

4 = 24

On putting B = 4, we get the ones digit 4 and remaining two B’s value should be 44.

For 6

7 = 42 and carry over 2 = 44

Hence A = 7 and B = 4

Ans. On putting B = 9, we get 9 + 1 = 10

Putting 0 at ones place and carry over 1, we get

For A = 7

7 + 1 + 1 = 9

Hence A = 7 and B = 9

Ans. On putting B = 7,

7 + 1 = 8

Now A = 4, then 4 + 7 = 11

Putting 1 at tens place and carry over 1, we get
2 + 4 + 1 = 7

Hence A = 4 and B = 7

10.

Ans. Putting A = 8 and B = 1, we get

8 + 1 = 9

Now again we add 2 + 8 = 10

Tens place digit is ‘0’ and carry over 1.

Now 1 + 6 + 1 = 8 = A

Hence A = 8 and B = 1