Use the charges particles model to show that 9+(-5)=4

http://oak.ucc.nau.edu/bmb9/MAT150/Integer%20Addition%20and%20Subtraction.pdf

I still don't understand

To use the charges particles model to show that 9 + (-5) = 4, let's consider positive and negative charge particles as representations of numbers. In this model, positive particles represent positive numbers, and negative particles represent negative numbers.

Step 1: Represent 9 with positive particles.
We start by representing 9 using positive particles. Let's say that each positive particle represents the number 1. Therefore, we would need 9 positive particles.

Step 2: Represent -5 with negative particles.
Next, we need to represent -5 using negative particles. Since each negative particle represents -1, we would need 5 negative particles in this case.

Step 3: Combine the positive and negative particles.
To combine the two sets of particles, we can put them together in a line. We will place the 9 positive particles first, followed by the 5 negative particles.

9 positive particles: +1 +1 +1 +1 +1 +1 +1 +1 +1
5 negative particles: -1 -1 -1 -1 -1

When we put these particles together, we can see that some positive and negative particles cancel each other out.

+1 +1 +1 +1 +1 +1 +1 +1 +1 (-1 -1 -1 -1 -1)

Step 4: Determine the remaining particles.
After canceling out the pairs of positive and negative particles, we are left with:

+1 +1 +1

Step 5: Summarize the result.
Since we have three positive particles remaining, each representing the number 1, we can conclude that 9 + (-5) equals 4 in the charges particles model.

+1 +1 +1 = 3

Therefore, 9 + (-5) = 4 based on the charges particles model.