Page 1 - Lesson Notes

SAI International School
CLASS-VI

Mathematics
CHAPTER-6: Integers
LESSON NOTE-3

SUBTOPIC: Addition of integers

Addition of integers without number line:

 The addition of two positive integers is simply the sum of two positive
numbers.
Ex- 2+3 = 5 or (+3) + (+2) = +5 [= 3 + 2].
 The sum of two negative integers is the same except that the answer will take
a minus sign.
Ex-(–2) + (–1) = – (2+1) = –3.
 When you have one positive and one negative integer, you must subtract, but
answer will take the sign of the bigger integer (Ignoring the signs of the
numbers decide which is bigger).
Ex-(+ 5) + (– 8) = 5 - 8 = (– 3)

Addition of integers with number line:

 Now we will learn to add integers using number line
Ex-Let us add 3 and 5 on number line. On the number line, we first move 3
steps to the right from 0 reaching 3, then we move 5 steps to the right of 3
and reach 8. Thus, we get 3 + 5 = 8.

 Let us add – 3 and – 5 on the number line. On the number line, we first move
3 steps to the left of 0 reaching – 3, then we move 5 steps to the left of – 3
and reach – 8. Thus, (– 3) + (– 5) = – 8.

 We observe that when we add two positive integers, their sum is a positive

integer. When we add two negative integers, their sum is a negative integer.