Observed arrival · 2026-11-08
Grid & Pen: feedback on the line that loses points
A math-practice tool that checks photos of handwritten work line by line and offers hints instead of worked answers.
○Open
⊠Login
$Paid
†Ads
✦Pretty
●Pro
◎Niche
◉Human
⚑Risk
ƒJS
- For
- Students practicing Algebra 1, Algebra 2, or AP Calculus AB
- Worth noticing
- Its FERMAT-dataset test reports 92 of 100 planted mistakes found, but also 75 flags among 189 solutions the dataset scores as correct.
Field notes
The workflow asks students to solve problems on paper, photograph their work, confirm the transcription, and inspect line-level feedback. The homepage lists Algebra 1 and 2 plus AP Calculus AB, with a free allowance of three checks per day. Its own dataset test also reports false flags among solutions scored correct, a limitation the site explicitly tells students to keep in mind.
Observed signals
Read the marks
Editorial observations of this landing page, not a rating.
○OpenPublic substance visible
⊠LoginAccess appeared gated
$PaidCommerce or pricing visible
✦PrettyNotable craft visible
●ProPolished or operationally mature
◎NicheUnusually specific use
ƒJavaScriptBrowser-side code central
One card from the complete issue