1. By Jonathan Ho and Theophilus Chan Fence of Thought To complete your mission, follow the steps described in the different windows to solve the problem. Click the home button anytime to exit.

2. Situation:

3. Which formula should we use to solve the problem? See problem again…

4. Sorry, please try again. Click to go back.

5. Good job! Now, the second step… (click here)

6. Which formula shouldnt we use to solve the problem?

7. Sorry, please try again. Click to go back.

8. Good job! Now, the third step… (click here)

9. Situation:

10. What is the best way to solve the problem? See problem again… Solve by linear equations Solve by a system of equations Solve by guess and check Solve by drawing a picture

11. Lets see… The problem couldnt be solved by a linear equation because there are 2 unknowns. Click to go back.

12. Lets see…

13. Guess and check would take too long. Click to go back.

14. Lets see… That wouldnt be a useful method to solve it. Click to go back.

15. Using a system of equations

16. THE SOLUTION… After solving the equation, use the numbers here to type in your answer. Your presses will be recorded in the computer automatically. Hint: The answer has 3 digits.

17. THE SOLUTION… After solving the equation, use the numbers here to type in your answer. Your presses will be recorded in the computer automatically. Hint: The answer has 3 digits.

18. THE SOLUTION… After solving the equation, use the numbers here to type in your answer. Your presses will be recorded in the computer automatically. Hint: The answer has 3 digits.

19. THE SOLUTION… After solving the equation, use the numbers here to type in your answer. Your presses will be recorded in the computer automatically. Hint: The answer has 3 digits.

20. THE SOLUTION… After solving the equation, use the numbers here to type in your answer. Your presses will be recorded in the computer automatically. Hint: The answer has 3 digits.

21. AND THE SOLUTION IS… Wrong! Click to go back, or click here to exit.

22. AND THE SOLUTION IS… CORRECT!!! Thank you for helping us complete the mission. Click to end your mission, or click here to participate in a LUCKY DRAW contest!

23. Lucky draw… Choose a door. If the door has a prize, you will get it. If it says Thanks for trying, then sorry!

24. Lucky draw… Choose a door. If the door has a prize, you will get it. If it says Thanks for trying, then sorry! Thanks for trying!

25. Lucky draw… Choose a door. If the door has a prize, you will get it. If it says Thanks for trying, then sorry! Thanks for trying!

26. Lucky draw… Choose a door. If the door has a prize, you will get it. If it says Thanks for trying, then sorry! You have won a pack of free food! Come later to claim.

27. Lucky draw… Choose a door. If the door has a prize, you will get it. If it says Thanks for trying, then sorry! Thanks for trying!