Calculator

Build a stripped-down instrument that takes two or three inputs and returns the one number the decision turns on. Unlike an open spreadsheet, the formula stays fixed and only the knobs that actually change the answer are exposed.

Build a stripped-down instrument that takes two or three inputs and returns the one number the decision turns on. Unlike an open spreadsheet, the formula stays fixed and only the knobs that actually change the answer are exposed.

Example

For the kitchen question you build a five-field tool: renovation cost, months until you start, monthly savings, current balance, emergency fund floor. It returns one number, your cushion on renovation day. Enter $40,000 and 14 months, see $3,200 left.