# Class 8 NCERT Solutions – Chapter 16 Playing with Numbers – Exercise 16.1

Last Updated : 24 Nov, 2020

### Question 1.

3  A

+    2  5

——–

B    2

——–

Solution:

A + 5  we get the unit digit as 2

if A = 7 , we get 7 + 5 = 12

The value of B = 1(carry) + 3 + 2 = 6

Hence the addition  is

3  7

+     2  5

——–

6  2

——–

Hence A = 7 and B = 6

### Question 2.

4    A

+    9    8

————

C    B    3

————

Solution:

A + 8 we get the unit digit as 3

if A = 5, we get A + 8 = 13

The values of B and C = 1(carry) + 4 + 9 = 14

1 is  taken as carry

Hence the addition is

4    5

+    9    8

————

1    4    3

————

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

### Question 3.

1   A

X           A

————-

9    A

————–

Solution:

A x A = A   if  A = 1 or 6

For A = 1

1  x 1 = 1  which is not equal to 9

For A = 6

6 x 6 = 36

1 x 6 = 6

Hence the multiplication is

1   6

X           6

————-

9    6

————–

Hence A = 6

### Question 4.

A   B

+   3   7

——–

6   A

——–

Solution:

A + 3 = 6

A = 6 – 3 = 3 = 2 + 1(carry)

A = 2

B + 7  we get the unit digit as 2

if B = 5 we get 5 + 7 = 12

Hence the addition is

2   5

+   3   7

——–

6   2

———

Hence A = 2 and B = 5

### Question 5.

A     B

X           3

————-

C     A      B

————-

Solution:

B x 3 = B

B = 0

A x 3 = CA

if A = 5  then 5 x 3 = 15

and  C = 1

Hence the multiplication is

5     0

X           3

————-

1      5     0

————-

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

### Question 6.

A     B

x            5

————-

C     A      B

————-

Solution:

B x 5 = B

B = 0 or 5

A x 5 = CA

if A = 5  then 5 x 5 = 25

and  C = 2

Only possible when B = 0

Hence the multiplication is

5     0

X           5

————-

2      5     0

————-

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

### Question 7.

A    B

Ã—        6

————

B     B     B

————

Solution:

B x 6 = B

if B = 4

4 x 6 = 24

where  2 is carry

A x 6 = BB

if A = 7

7 x 6 = 42

Hence multiplication is

7     4

Ã—        6

————

4     4     4

————-

Hence A = 7 and B = 4

### Question 8.

A    1

+  1     B

———–

B    0

———–

Solution:

1 + B  we get unit digit as 0

if B = 9

1 + 9 = 10

where 1 is the carry

1(carry) + A + 1 = B = 9

A + 2 = 9

A = 9 – 2 = 7

7    1

+  1     9

———–

9    0

———–

Hence A = 7  and B = 9

### Question 9.

2     A    B

+  A     B    1

—————

B     1    8

—————

Solution:

B + 1 we get the unit digit as 8

if B = 7

7 + 1 = 8

A + 7  we get the tens digit as 1

if A = 4

4 + 7 = 11

where 1 is the carry

1(carry) + 2 + 4 = 7

2     4    7

+  4     7    1

—————

7     1    8

—————-

Hence A = 4 and B = 7

### Question 10.

1    2    A

+  6    A     B

—————-

A     0     9

—————-

Solution:

A + B  = 9

if A = 8 and B =1

8 + 1 = 9

2 + A = 0

if A = 8

2 + 8 = 10

where 1 is the carry

1(carry) + 1 + 6 = A = 8

Hence the addition is

1    2    8

+  6    8     1

—————-

8     0     9

—————-

Hence A = 8 and B = 1

Previous
Next