Page 36 - Revised Maths Wisdom Class - 6

34 MATHS

ACTIVITY TIME
ACTIVITY TIME

Objective:

To understand the rules of addition of integers.

Materials Required:
Red and green plastic coins, cardboard.

Procedure:

1. Consider each red coin as negative unit and green as positive unit.

2. Take 4 red coins and 3 green coins. This represents – 4 and + 3. Add them as below.

R R R R + G G G

3. Remember the rule of additive inverse, i.e., each –ive cancels each +ive.
Here, –4 + 3 = –1 as one red coin is left. Thus –4 + 3 = –1

4. Similarly, add (+4 and +3), (+4 and –3) and (–4 and –3) and find the result.
Observations:

– 4 + 3 = –1

+ 4 + 3 = +7

+ 4 + (– 3) = +1

– 4 + (– 3) = –7

Conclusion:
(a) When we add two integers of same sign, we put the sign of the two integers to their sum.

(b) When we add two integers of different sign, we subtract them as whole numbers and put the sign
of the integers with greater numerical value to the difference of the two numbers.