Here is the simplest version, one that we started with in class:
Digit Place Game
Objectives: Students will learn the concept that each digit has its own unique place within the whole number.
Materials: chalkboard, chalk (or paper, pencil at home)
I said, "We're going to play a game called the Digit-Place game. It's a guessing game, and I will write down my secret number on a piece of paper. You can make guesses and I give you clues on a chart." I then drew a simple chart on the board that said NUMBER/DIGIT/PLACE.
We started with a two-digit number. As children guessed numbers, I wrote their number under "number" and then wrote how many correct digits were in their guess, and how many were in the right place. Then the students kept guessing numbers based on the previous responses, until we got the right number. We are currently up to guessing numbers in the thousands place - it is getting super tricky!
An example would be 25. If a student guessed 51, I would write 51 under number, then 1 under digit (meaning that the digit 5 was guessed correctly), then 0 under place (meaning that it was not in the correct place). If the next guess was 45, then I would make the notation as follows:
NUMBER DIGIT PLACE
51 1 0
45 1 1