The expression combines two negative numbers. When you subtract a positive number (in this case, 4) from a negative number, you essentially move further away from zero on the number line. So, if you start at -5 and take away 4 more, you end up at -9. It’s like a downward journey into the negative realm!

Now, if you’re ever plugging this into a real-world scenario, consider finances. If you owe $5 and then add another debt of $4, you’re not just in the red; you’re now $9 in the hole! Understanding how to navigate these negative numbers can help you manage budgets and expenses effectively.