According to David Glover (2006), **adding and subtracting integers** is a method used to calculate or subtract a total of two or more numbers. It is one of the most important basic arithmetic operations. The addition operation is denoted by a plus sign “+” and subtraction with the symbol “-“.

Adding and subtracting of integers are addition and subtraction operation used to calculate the total of two or more integers. These are the most basic mathematical concept that must be mastered by everyone. There will not be any other concept without these operations.

**Basic Concept of Integer Operations**

**1. Adding and Subtracting Integers** Operations Using Number Lines

A number line is a straight-line drawing with points that are assumed to be ordered real numbers. The addition of numbers can be done with the help of a number line, here is an example. Do the following addition using a number line!

2 + 3 =…

**Answer**: Attached figure 12.1

**Steps**:

- Draw a number line
- Draw line I: Draw a line from zero along 2 units (2)
- Make line II: Draw a line from the end of line I along 3 units (3)
- Draw line III: Draw a line from zero to the end of line II
- The sum is shown by line III, 2 + 3 = 5

**2. Adding and Subtracting Integers** Operations Using Composite Method

Adding numbers with relatively large numbers will be difficult to do with the help of number lines. The solution is to use the tiered method. To use long addition, we must understand adding the numbers one to 10. Here’s an example of a problem.

Complete the following addition with the following addition in order!

123 + 68 =

**Answer:** Attached figure 12.2

**Steps:**

- Write the numbers that are added together, units parallel to units, tens parallel to tens, and so on.
- Perform the addition from the right (unit) to left
- The number of units 3 + 8 = 11. Write the number 1 in the sum of units and save 1 in tens.
- The sum of tens 2 + 6 = 8, because previously saved 1 in tens, then add the results again with the numbers stored, namely 8 + 1 = 9. Write the number 9 in the sum of tens
- Addition of hundreds of 1 + 0 = 1. Write the number 1 in the sum of hundreds
- Thus, 123 + 68 = 191

**Example of Adding and Subtracting Integers Operation**

### Question

Here is an example of this integer operations. A shark is 200 meters below sea level, the top of a hill is 800 meters above sea level. If an airplane is 2 kilometers up a hill, what is the difference between the shark and the plane?

### What We Know

To find out the result, we can use integer operations, namely addition, and subtraction. There are several concepts that are important for you to pay attention to. First, we have to know, if the addition which meets the negative sign will be a subtraction operation.

For example, 3+(-1)=2, then 3+(-2)=1. Whereas in the subtraction table, if the subtraction meets a negative sign, it will be an addition operation. An example is 3-(-1)=4. After understanding this concept, you can answer the **adding and subtracting integers** questions above.

It is known that the shark=-200 meters, the height of the top of the hill=800 meters, and the plane=2 kilometers or 2,000 meters on the hill. From the information above, it can be solved with the equation, plane=800meters+2,000 meters, then the result is 2,800 meters.

### The Answer

The difference between planes and sharks = 2,800 meters – (-200 meters) then it is equal to 2,800 meters + 200 meters, the result is 3,000 meters or 3 kilometers. So, the difference between the plane and the shark is three kilometers.

From the problem solving above, we learn that integer operations are necessary for our daily life. Everything in our life is needed to be counted because that is how life works. Then, a deeper understanding of **adding and subtracting integers** operation is a must.