### Using the Number Line

When we **add**, we move **right** on the number line.

When we **subtract**, we move **left** on the number line

### Adding Integers

* Example:*

To evaluate –3 + 2 , we start at –3 and move 2 places to the right

The answer is –1

### Subtracting integers

To evaluate –3 – 2 , we start at –3 and move 2 places to the left

The answer is –5

**How to add integers and subtract integers using the number line?**
**How to think about adding and subtracting integers on a number line?**

#### Using Rules to Add Integers

Using the number line to add or subtract integers may be quite tedious. A quicker method would be to use the following rules:

** Rule 1 : **

The sum of two or more positive integers is a positive integer.

The sum of two or more negative integers is a negative integer.

* Example:*

(+7) + (+ 4) = + 11

(– 8) + (– 9) = – 17

**Rule 2 : **

To find the sum of a positive and a negative integer:

Subtract the two numbers (ignore the signs) and then keep the sign of the larger integer.

(– 9) + (+ 7) = – 2

(– 3) + (+ 5) = + 2

**Rule 3 : **

The sum of an integer and its opposite is equal to zero

(– 9) + (+ 9) = 0

(– 3) + (+ 3) = 0

**How to use the rules to add integers?**
#### Using Rules to Subtract Integers

To subtract integers, we can rewrite the subtraction problem as an addition problem. Instead of subtracting, we add the opposite.

- Subtracting a positive is the same as adding a negative.

3 − (4) = 3 + (−4)

- Subtracting a negative is the same as adding a positive.

3 − (− 4) = 3 + 4

We then follow the rules for adding integers.

**Basic rules for subtracting integers and provides examples**
Each subtraction problem is
rewritten as an addition problem.

**Subtracting Integers using Rules**

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