Create a grid in Word (or mine is in Google Drive) with letters along the left and numbers on the top.
Letter it A-H horizontally and number it 1-8 vertically.
Project the grid (empty), and print a copy for yourself. On your copy, write down random numbers from 10 to 50 in all of the different empty squares.
Ask the students questions. When they answer correctly, they can choose a points square by choosing an intersection. Check your grid to determine if they will earn 10-50 points. This keeps the game exciting because a group can jump into the lead at almost any time.
Another option is to give each group a whiteboard. They must write the correct answer and show it first.