|RAD-DEG||Assuming the display is in Radians, convert to Degrees|
|DEG-RAD||Assuming the display is in Degrees, convert to Radians|
|SIN||Compute the Sine of the display|
|SIN-1||Compute the ArcSine of the display|
|COS||Compute the Cosine of the display|
|COS-1||Compute the ArcCosine of the display|
|TAN||Compute the Tangent of the display|
|TAN-1||Compute the ArcTangent of the display|
|1/X||Compute the Inverse of the display|
|LOGeX||Compute the Natural Logarithm of the display|
|LOG10X||Compute the Base-10 Logarithm of the display|
|ex||Compute the Natural Exponent of the display|
|10x||Compute the Base-10 Exponent of the display|
|X2||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|
For convenience, two of the main registers are available directly using the "left" and "right" access keys, located to the left and right, respectively, of the central numeric keypad. These keys have the following functions:
|TOTAL||Move register value into display, and clear register|
|STORE||Copy display value into register|
|RECALL||Copy register value into display|
|+||Add display to register, copy sum back into display|
|-||Subtract display from register, copy difference back into display|
|×=||Multiply register by display, copy product back into display|
|÷=||Divide register by display, copy quotient back into display|
The "left" register is register 15, the "right" register is register 14.
The rest of the main registers may be accessed using the same functions, but by using the pushbuttons labeled "T" (TOTAL), "+", "-", "×", "÷", "St" (STORE), and "Re" (RECALL). This is accomplished by depressing one of the pushbuttons, for the desired function, and then pressing one of the keys 00 through 15 to perform that function on the specified register. No action is taken until one of the keys 00 through 15 is pressed, in other words changing the pushbuttons takes no action by itself it only prepares an action for when a key is pressed.
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|
So, the answer is that 70 degrees Fahrenheit equals (approximately) 21 degrees Celsius.
Using the extended registers normally requires constructing a special code that is not normally created by keys on the keyboard. This is done using the pushbutton switches labeled "1" through "7", and "8" (or "Sp"). The pushbutton "8" actually adds 8 to the value selected by "1" through "7" (if none of "1" through "7" are depressed, then the value "0" is used). So, to create the code for register 15 06, you would depress pushbuttons "7" and "8", then press the key 06. So, to recall the value of register 15 06, you would press RECALL (not the blue left or right keys, but the green key in the right-most keypad) and then, with pushbuttons "7" and "8" depressed, press the 06 key.
While no math functions may be performed directly on extended registers, there is a way to indirectly access these registers. If the register number is converted to a decimal value, as such register 01 00 would be "16", and that value is stored in one of the main registers, then the INDIR key may be used in conjunction with the normal math functions on main registers to perform that same math function on an extended register. For example, if the value "16" were stored in register 00, then performing a INDIR +00 would add the display to register 01 00 (not register 00 00).
Converting a register number (pair) to a decimal value is done by multiplying the first number by 16 and adding the second. For example, register 15 06 would be 15 * 16 + 6 or 246.