Option A: Gemini Notebook: cited ladder and solution guide
Best when: You want to audit the ladder against the worked example
What it does: Gemini Notebook drafts with citations; you correct and test
Strong at: Each rung cites the source step it comes from
Limit: Needs your check that support removal is fair
Free plan: Yes, limited (notebook and source caps)
Option B: ChatGPT: generates variants, you set the ladder
Best when: You want rung difficulty set by your own solving
What it does: ChatGPT generates and formats; you solve and rank
Strong at: Rungs follow the difficulty you actually experienced
Limit: You must solve every variant yourself
Free plan: Yes, limited (uploads and data analysis)
Option C: ChatGPT: drafts the rungs; Photomath checks the last
Best when: You want a second solver on the final rung
What it does: You plan; ChatGPT drafts and compares; Photomath solves
Strong at: Independent solution of the final rung
Limit: Photomath does not analyse a supplied worked solution
Free plan: ChatGPT: Yes, limited (uploads and data analysis); Photomath: Yes