“Lickety Split ice cream cones sell for $1.75 each. The Yummy Tummy sells ice cream cones for $2.15, each but will give you a free cone after you buy five. One store is offering the better deal. How much will you save if you buy six ice cream cones at that store?” Do you remember these sort of problems in your math class? Problems about various trains leaving different stations at various times, and then having to answer which one arrived where, when? Problems about oranges and bananas and buying twice as many of one and dropping half and how many were left to give to your neighbor if you’d already given a fourth to your friend? I hated those sort of problems. They were theory wrapped in practical packaging, but I always thought if I really wanted the ice cream I’d figure out if I had the …