Trace the assignments carefully
When a problem asks you to trace variable assignments, the goal is to follow how each variable changes step by step. The final answer depends on the value stored after every assignment has been applied.
Method
- Start with the initial values. If the problem gives starting values, write them clearly.
- Read one statement at a time. Update only the variable named in that statement.
- Replace old values with new ones. If a variable is assigned using other variables, use their current values at that exact moment.
- Keep a small table or list. This helps you avoid mixing earlier and later values.
- Simplify the final result. If the exercise asks for a simplified answer, reduce the expression or final value as far as possible.
Common mistake to avoid
Do not use the original value of a variable after it has already changed. Each new assignment overwrites the previous one.
Check your work
Re-read the steps in order and verify that every update matches the last value before it. If possible, substitute the final values back into the last expression to confirm the result.