Help with keypad

Me and a friend are trying to make a calculator as a school project and we nee help.
Here are some questions:

1:How do you put the input from your keypad to your lcd display?
2:Is it possible to use multiple digit numbers with a keypad?

1:How do you put the input from your keypad to your lcd display?

What keypad? What LCD display?

There are examples in each library for reading from/writing to the appropriate device. It is not rocket science to merge them.

2:Is it possible to use multiple digit numbers with a keypad?

Of course. What does pressing '1' and then '3' mean to you? It means exactly the same thing to the Arduino, if you write the code properly.