In this investigation, students can explore factorials (like 5! = 5x4x3x2x1) using a program like Yacas to calculate the larger values when their calculators run out of steam. Students can come up with some of their own questions (Why does 6000! have that many zeroes?) or teachers can offer suggestions for problems (look at 1/0! + 1/1! + 1/2! + 1/3! + … to see if you spot a pattern).