Solve the Addition: 3600 + 900 Step by Step

To solve this problem, we will perform a simple addition:

Step 1: Identify the numbers to be added:
The numbers are $3600$ and $900$.

Step 2: Align the numbers by their place value. Since they are both whole numbers, the alignment is straightforward:

• $3600$

• $+900$

Step 3: Add the numbers starting from the right:

$\begin{aligned} &3600 \\ +&\underline{\phantom0900} \\ &4500 \\ \end{aligned}$

Therefore, the sum of $3600 + 900$ is $4500$.