Page 285 - Ganit Kaushal

Ex 22. Below is a grid having some numbers. Follow the steps as given until no number is left. (NCERT)

Circle any number
3 4 0 9
–2 –1 –5 4 Strike out the row and column
1 2 –2 7 of the chosen number
–7 –6 –10 –1
Circle any unstruck number

When there are no more unstruck numbers, STOP. Add the circled numbers.
The procedure of circling and striking off the row and column in which the circled number lies, gets
completed in four steps as shown below:

3 4 0 9 3 4 0 9 3 4 0 9 3 4 0 9
–2 –1 –5 4 –2 –1 –5 4 –2 –1 –5 4 –2 –1 –5 4
1 2 –2 7 1 2 –2 7 1 2 –2 7 1 2 –2 7
–7 –6 –10 –1 –7 –6 –10 –1 –7 –6 –10 –1 –7 –6 –10 –1

In the example our circled numbers are – 1, 9, – 7, – 2. If you add them, you will get – 1.
Now answer the following questions:
(a) Try afresh, choose different numbers this time. What sum did you get? Was it different from the
first time? Try a few more times!

(b) Play the same game with the grids below. What answer did you get?

7 10 13 16 –11 –10 –9 –8
–2 1 4 7 –7 –6 –5 –4
(i) (ii)
–11 –8 –5 –2 –3 –2 –1 0

–20 –17 –14 –11 1 2 3 4
Sol. (a) (−1); No, every time we get the same answer, i.e., (−1).

(b) (i) −8 (ii) −14

Miscellaneous Exercise 10.4

There are four options (Q. 1 to Q. 10), out of which only one is correct. Choose the correct option.

1. The sum of two integers is −17. If one of them is −9, the other is
(a) 8 (b) −8 (c) 26 (d) −26
2. The statement “When an integer is added to itself, the sum is less than the integer” is

(a) always true (b) never true
(c) true only when the integer is negative (d) true when the integer is 0 or positive

3. The number of integers between –4 and 4 is
(a) 4 (b) 5 (c) 6 (d) 7
4. 5 more than –2 is
(a) 1 (b) 2 (c) 3 (d) –3

The Other Side of Zero 283