Problem A

Adding and Subtracting

Follow the steps below.

**Step 1:** Pick two different three-digit numbers. Label the larger number \(A\) and the smaller number \(B\).

**Step 2:** Subtract \(B\) from \(999\) and label the difference \(C\).

**Step 3:** Add \(A\) and \(C\) and label the sum \(D\).

**Step 4:** Subtract \(1000\) from \(D\) and label the difference \(E\).

**Step 5:** Add \(1\) to \(E\) and label the sum \(F\).

What is the connection between the number \(F\) and the numbers \(A\) and \(B\)?

Try the same steps with different numbers. Do you think you will always get the same result? Why or why not?

**Themes:** Computational Thinking, Number Sense