Answer:
The biggest number he can make is 348. Hope this helps!!!
Explanation:
You have to multiply 4 and 7 together to get 28. Since if we multiplied every number together, we would end up with a lesser number, since anything multiplied by 1 is itself. Therefore, you next add 1 to 28 to get 29. Finally multiply 29 by 12 to get 348.