A better palette of possible factors was something I thought about. It will require rewriting nearly the whole app, but it's likely the direction I'll go when I make v2.

To take it a step further I thought I could use even smaller building blocks via dimensional "toolboxes" like quantity, distance, volume, and conversions and each question files its factors into each tool box (with some dummies like you said). Do you think that'd be more interesting? It's more complex though so mass appeal might go down.