Summation based benchmark for calculators

[Michael de Estrada]

Elektronika MK 54, MK 56 and MK 61

These are Soviet RPN programmable calculators from the mid 1980s to the early 1990s. They are extremely slow, so I only have results for 10 loops.

MK 54: 10 loops —> 99 seconds, Result = 13.711835

MK 56: 10 loops —> 110 seconds, Result = 13.711835

MK 61: 10 loops —> 100 seconds, Result = 13.711835