LTP-16C - a base-8 and base-10 postfix calculator and solver

OCT·8 / Reverse Polish & Solver

Octal0

Base 100

Stack trace

Type an expression to watch the stack build.

One line, two jobs: Type an expression and it computes. Put an = in it and the same line becomes a function to solve.
Order: Values first, operator last. 1 4 / divides 1 by 4. Put a space between every token.
Base: Oct takes 0–7, so 10 is eight and 0.4 is one half. Dec wakes the 8 and 9 keys. The other base is always on the second display line.
Negative and powers: NEG writes the minus flush against the digits, as in 10 -5 +; spaced out it subtracts. 2 3 ^ is a power, 4 0.4 ^ a square root.

Definition: Both sides in RPN with = between them. FUNC at the end is optional.
Variables: The X key then a digit: X0, X1, X2. Each one gets a field.
Solving: Fill in every value but one. The empty field shows its answer in gold, whichever side of the = it sits on, and the trace lists each step undone.
Two answers: Undoing an even power gives a pair, so the display lists both tuples.