GitHub - ahmed-Nasr-Eldin/64-bit-Calculator-8051: 64 bit unsigned number calculator implementation over 8051 microprocessor and the UI of this project is the terminal which connects with controller via UART.
Windows Calculator - Wikipedia
16 bit calculator with 4 functions. : r/redstone
E2090 64 Bit Hexadecimal/20 Digit Calculator | Locus Engineering Inc.