What you see when you tap
Every answer card has a small expand affordance. Tap it, and the card unfolds into the formula and its calculation chain. For a rafter length, that's the pitch ratio, the run, the Pythagorean step, and the rounding to your chosen precision — each as its own line, each with the numbers you provided substituted in.
For simple formulas, two or three steps. For pitched roof or complex framing math, six or seven. The point isn't to make the math look impressive. The point is to let you verify when something doesn't look right.
Edit any input, see the answer recalculate
The expanded answer card lets you tap any input value and adjust it. Change the pitch from 6/12 to 8/12 and the answer updates live. Change the span from 28 feet to 32 feet and the rafter recalculates. You can ask the original question by voice once, then explore the parameter space with your finger.
Why this exists
Apprentices learn formulas. Crews want to teach without lecturing. Foremen need to spot-check work without re-deriving the math. A tool that hands you a number and walks away makes everyone dumber over time. A tool that shows the work makes the crew sharper.
And honestly: when a calculator gives you a weird answer, you want to know why. Show the Math is the first place to look.