Definition of terms:

Directed numbers: are negative and positive numbers, so we are going to learn how to add, subtruct, multiply and divide directed numbers in easy way.

Positive numbers:

List of some positive numbers.

1, 5, 7, 3, 100, 55, 2, 9, 400, 0.6

Negative numbers:

List of some negative numbers.

-1, -5. -7, -3, -100, -55, -2, -9, -400, -0.6

Addition of directed numbers:

To add directed numbers we need to look at big and small number.

Worked Example:

Lets take a look at 5 + 3.

The answer of 5 + 3 is 8.

5 + 3 = 8

BUT:

5 + -3 is not 8.

The answer is 2.

5 + -3 = 2

Why we donot get same answer when adding 5 + 3 and 5 + -3 ?

This is because 5 and 3 as they are positive numbers we can say is what we have maybe we can say we have 5 pens and 3 pens so, when adding them together we get 8 which is the sum of what we have (pens).

So, 5 and -3 are different because 5 is a positive number while -3 is a negative number and we can say 5 is what we have while -3 is what we donot have. We can say we have 5 pens but we donot have 3 pens, so to indicate these 3 pens that we donot have we can just put negative sign and we have -3.

So, how did we get 2 when adding 5 + -3 ?

As 5 is bigger than 3, we just subtructed 3 from 5 then we get 2 and we subtructed what we donot have from what we have so that we can know what we realy have.

5 + -3 = 2.

So, lets see if we have 3 pens and we donot have 5 pens. We are going to represent 5 pens that we donot have with -5. We just put negative sign to 5.

Worked Example

Lets add 3 and -5.

3 + -5 = -2

As 3 is less than 5 we subtruct it from 5 and we get -2 because the negative sign is on bigger number which is 5 so, we take the sign with 2 then answer is negative 2 (-2).

What if we donot have 5 pens and 3 pens?

Remember we represent what we donot have with a negative sign, therefore the numbers are -5 and -3.

Worked Example

Lets add -5 and -3.

-5 + -3 = -8

We get -8 because both numbers have same sign (-5 and -3), so we add 5 and 3 which is 8 then take negative sign to 8 and the answer is negative 8 (-8).

We can follow this procedure to all numbers only when we add directed numbers.