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\ 07-Nov-2024 Bharat Arora Proof-8 Reader’s Sign _______________________ Date __________

Since, a red and a blue counters cancel each other and give the numerical value ‘0’.

So, we are left with two red face counters and its numerical value = + 2

Hence, +5 + (–3) = +2
Example 13: Add the following using counters:

(a) (–6) + 3 (b) 5 + (–4)

Solution: (a) (–6) + 3

\ –6 + 3 = –3

(b) 5 + (–4)

\ 5 + (–4) = 1
Subtraction of Integers using Counters/Tokens

If 2 red counters represents +2 then two blue counters represents –2. Or, if we invert the red face
counter to get blue face it simply means the change in sign from ‘+’ to ‘–’.
Let’s understand it with example.

Example 14: Subtract: (–3) – (– 4)

Solution: Take 3 counters and place them in a row so that their top faces are blue. Now, take another
4 counters and place them in the second row so that their top faces are also blue.

Since, we have to subtract (–4) so the blue counters at the second row has to be inverted to get red
faces of counters.

(–3) – (–4) = +1

295 The Other Side of Zero