**Compare a graphing calculator with a smart phone.**

If your students are in high school, then they probably carry around something like a TI-83 Plus calculator, which contains a 6MHz Z80 processor, 27 kB of user RAM, and a 96×64-pixel monochrome display. That's the same processor and similar specs as an Osborne 1, which was sold in 1976 for over \$4,000 (in today's money) or a TRS-80, which was sold in 1977 for $2,400.

Place a graphing calculator along-side a smart phone. Ask your students whether they'd rather pay \$5,000 for the calculator or $500 for the smart phone. In 40 years, processors and memory have improved by a factor of 1,000, desktops have shrunk to pocket-sized, and cost has dropped by a factor of 10.

The reason why a graphing calculator costs \$100 instead of \$10 is beyond the scope of the question, but it makes more sense of you think of calculators as a necessity for passing a class (no smart phone apps allowed).