Classic Calculators

TI-Businees Analyst-I

The TI-Buisness Analyst I was released in 1977. This obviously did Business Math and also performed the regular functions of  a basic math calculator. I happen to have one of these, along with  a TI SR-40. The TI-Business Analyst I ran on one 9-volt battery.

TI SR-40

The TI SR-40 was released in 1976. It performed Algebreic equations, along with basic math. Unlike the TI-Business Analyst I, this had  a rechargable battery.