• Step 1: When you see a number in the expression, type it in the input box and click Push to add it to the stack.
• Step 2: When you see an operator (+, -, *, /, ^), click the corresponding operator button. This will:
  • Automatically pop the top two numbers from the stack
  • Perform the operation
  • Push the result back onto the stack
• Step 3: Repeat steps 1 and 2 until you've processed the entire expression.
• Step 4: When finished, the stack should contain exactly one number (the final answer). Do NOT click Pop - the result must stay in the stack!
• Step 5: Click Check to verify your answer.

Important: The Pop button is only for correcting mistakes. The final answer should remain in the stack, not in "Popped Elements".

Example: For 5 3 +:
1. Push 5 → Push 3 → Click + button
2. Stack now shows: [8]
3. Click Check (Do NOT click Pop!)