The Adventure of the Little Dragon

Does your child think that math is boring? We will convince him otherwise! The future straight-A student must help the little dragon who is trying to find his lost parents! And as a reward, the winner will receive… a cartoon.
What needs to be done:
1) Solve interesting logical puzzles to collect key answers.
2) Substitute the collected keys into the final puzzle and find the code.
3) Scan the QR code and enter the resulting combination of numbers.
If the child makes no mistakes, he will see an animated story about how the little dragon reunites with his parents.