I used an HP calculator in college (they didn&#x27;t exist when I was in high school). But now life is no longer so simple. Now you&#x27;re forced to use a very overpriced POS TI graphing calculator. Besides, most high school math teachers probably don&#x27;t even know what RPN is!<p><a href="http:&#x2F;&#x2F;mic.com&#x2F;articles&#x2F;125829&#x2F;your-old-texas-instruments-graphing-calculator-still-costs-a-fortune-heres-why" rel="nofollow">http:&#x2F;&#x2F;mic.com&#x2F;articles&#x2F;125829&#x2F;your-old-texas-instruments-gr...</a>