Key | Function |
---|---|

1/X | Compute the Inverse of the display |

LOG_{e}X | Compute the Natural Logarithm of the display |

LOG_{10}X | Compute the Base-10 Logarithm of the display |

e^{x} | Compute the Natural Exponent of the display |

10^{x} | Compute the Base-10 Exponent of the display |

X^{2} | Compute the Square of the display |

INT X | Truncate the display to an integer |

√X | Compute the Square Root of the display |

|X| | Compute the Absolute value of the display |

The register operations available are:

Key | Function |
---|---|

STORE (or ↑) | Copy X display value into register |

RECALL (or ↓) | Copy register value into X display |

+ | Add X display to register |

- | Subtract X display from register |

×= | Multiply register by X display |

÷= | Divide register by X display |

↑↓= | Exchange register with X display |

The target register is selected based on the address keywords INDIR (indirect, using Y display), DIR or DIRECT (second key code is register number), or none (implied) as Y display.

For DIRECT addressing, register numbers may be entered using the toggle switches and keys 00 through 15. Note, register numbers are effectively interpreted as decimal so using the keys 10 through 15 is not recommended. The toggle switches are used to form the first digit of the register number, normally 0-9, in binary. Special codes exist for accessing registers above 99, but do not have dedicated keys. In the case of accessing register above 99, the first digit may range above 9 in order to access register above 199. For example, register 243 may be accessed using the "DIR+100" codes and register "number" 14 03 (143 + 100 = 243).

C = (F - 32) * 5 / 9

Note, the calculator has no concept of precedence or parenthesis,
so the calculation must be performed in
a deliberate order so that precedence is maintained.
The first part to perform is the `F - 32`.
Next, that result is multiplied by 5.
Finally, that result is divided by 9.
Note, an alternate order is
to compute `5 / 9` (and possibly store it someplace more permanent)
and then multiply by that pre-computed value.
For simplicity in example, the first approach is used.

So, the steps required to convert 70 degrees Fahrenheit into degrees Celsius would be:

Key | Display, after pressing key |
---|---|

7 | +.000000000000 |

+7 | |

0 | +.000000000000 |

+70 | |

↑ | +70.0000000000 |

+70.0000000000 | |

3 | +70.0000000000 |

+3 | |

2 | +70.0000000000 |

+32 | |

- | +38.0000000000 |

+32.0000000000 | |

5 | +38.0000000000 |

+5 | |

× | +190.000000000 |

+5.00000000000 | |

9 | +190.000000000 |

+9 | |

÷ | +21.1111111111 |

+9.00000000000 |

So, the answer is that 70 degrees Fahrenheit equals (approximately) 21 degrees Celsius.