Middle schoolers speculate on the better rate of pay: a dollar a day for 10 days, or a penny the first day, two pennies the second, doubling each day for 10 days. Start by listening to the story The King's Chessboard, by David Birch. They calculate the amount the peasant will receive. None of the links are active on this instructional activity, so the teacher will need to create their own based on the description.