Page 23 - Maths Skills - 7

Integers 21

Word Stock
Property Quiz Gain Loss Predecessor Successor Process Product

Activity

Objective: To understand the rules of addition of integers.
Pre-Requisite Knowledge: 1. Negative numbers are smaller than positive numbers.

2. Addition of a positive integer and its negative is zero.
Materials Required: Compass box, ruler, coloured papers (red and green), fevicol, a pencil

Procedure: 1. Take a white sheet and cut off squares each of 1 cm side. This represents a positive unit integer
or (+1) as shown in Fig. 1.
2. Similarly, take a coloured sheet and cut off squares each of 1 cm side. Positive Negative

This represents a negative unit integer or (–1) as shown in Fig. 1. (+) (–)
3. Let the integers to be added be (+3) and (+4). Fig. 1

4. Paste three squares in the first row and four squares in the second row. As both the integers
are positive, so count the total number of squares which is the result, i.e., (+3) + (+4) = (+7) as
in Fig. 2.
Addition of: (i) two +ve integers (ii) two –ve integers

(+ 3) + (+ 4) = + 7 (– 3) + (– 4) = – 7

(iii) +ve and –ve integers (iv) –ve and +ve integers

(+ 5) + (– 2) = + 3 (– 5) + (+ 3) = – 2

Fig. 2
5. Similarly, take the integers of your choice and repeat the same process to find the result.
* Do not forget to cancel one white square against one coloured square while adding negative

and positive integers.
6. Paste the squares on left side according to your problem and record your observations in the
given table. Draw another table if required.

Observations: S. No. Examples Result

(i) (+3) + (+4) = (+7)

(ii)

(iii)

(iv)