Here's great math game to play with 3-6. You might try it w/ 2nd graders using only 2 digits. It is Math Mastermind. If you have ever played the game mastermind, it's a lot like that, but with numbers instead of colored pegs. Tell the class that you are thinking of a 3 digit number, and their job is to guess what it is. Call on a student, who will guess a random number. Lets say they call out 492. Write this number on the board. Next to it have 2 columns. Label one column CORRECT DIGIT, WRONG PLACE, the other column label CORRECT DIGIT, CORRECT PLACE. Lets say the number you are thinking of is 519. You would then put a 1 in the 1st column (correct #, wrong place), and 0 in the 2nd column (because the 9 in 492 is in your number (519), but it is not in the right place). Using that information, call on another student to guess the number. If they are paying attention, they will say a number with a 4,9, or 2 in it to see if one of those is the number in your digit. Suppose they say 359. You would write this number under the first number they said. You would then put a 1 in the first column, and a 1 in the 2nd column. (the 5 is a correct digit, wrong place and the 9 is the correct digit, correct place). It is really a great game, and I have had a lot of success with it. It sounds more complicated than it is. Try it once, and you will see it is easy to execute. Not always so easy to figure out the number, though!