HP 35 calculator 200 trick
![Image](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7Qs3a127ifmyyyzoeMHAm0ThBxWX9oy0tAekeHzywLl2VRlLjyZ0T4xgVeOeoboSRnXcDN3JMMqi3FxA-WVR76JqREM5OOqmpsqN-qDyerQ4Ldvziayo4j5VXI12DwdIAggytuXx5FVhZdTd4MsT-4MtlIz4LKap2P8KAN60qXf8tQARUcrOOTD__Qg/s320/HP-35_Red_Dot.jpg)
In 1972 I bought the first HP 35 calculator sold on the Caltech campus. It was not by far the first one on the campus – HP had distributed pre-release copies to numerous faculty members. Max Delbrück, my next-door neighbor, had given me my first experience with the calculator one evening while hosting my landlady, her family, and me for dinner. I was smitten. When the Caltech Bookstore posted the impending availability of the calculator I was the first on the list. The arrival date was not known, so I haunted the bookstore. HP-35 (Source: https://commons.wikimedia.org/wiki/User:Mister_rf) They finally came in sometime in November of 1972, if I remember correctly, and I happily paid the $395 price (about a quarter of my life savings at the time). It was everything I had dreamed of and more. It transformed my Physics lab performance from C (great on execution and writeup, not so hot on accuracy of calculation) to A. It made me popular as a member of study groups. Games with HP 35