Addition of Integers

We will learn addition of integers using number line.

We know that counting forward means addition.

Addition of Two Positive Integers:

When we add
positive integers, we move to the right on the number line.

For example to add
+2 and +4 we move 4 steps to the right of +2.

Thus, +2 +4 = +6.

Addition of Two Negative Integers:

When
we add two negative integers, we move to the left on the number line.

For example to add -2 and -4 we move 4 steps to the left of -2.

Thus, -2 + (-4) = -6.

Addition of a Negative Integer and a Positive Integer:

When a negative integer is added to a positive integer we
move to the left on the number line.

For example to add +2 + (-4), we move 4
steps to the left of +2.

Thus, +2 + (-4) = -2.

Addition of a Positive Integer and a Negative Integer:

When a positive integer is added to a negative integer we
move to the right on the number line.

For example to add (-6) + 3, we move 3
steps to the right of -6.

Thus, (-6) + 3 = -3.

We can add two integers having same sings by adding their
absolute values and placing the common sign of two integers before it.

Solved Examples on Addition of Integers:

1. Find the value +18 + (+5)

Solution:

Absolute value of |+18| = 18

Absolute value of |+5| = 5

Sum of absolute values = 18 + 5

Since, both integers have common sign +, we place + sign in
the answer.

Hence, +18 + (+5) = +23.

We can add two integers having opposite signs by finding
difference of their absolute values and placing the sign of the integer with
the greater absolute value before it.

2. Find the value -38 + (+28)

Solution:

Absolute value of |-38| = 38

Absolute value of |+28| = 28

Difference of absolute values = 38 – 28 = 10

Placing the sign of the integer with the greater absolute
value = -10

Hence, -38 + (+28) = -10.