Android waitlist open

Three days.
Three circles.
Mastered.

Sanmaru turns the problems you got wrong into a few minutes of re-solving each day — until you’ve got each one right on three different days.

One email when Android is ready. Unsubscribe anytime.

One problem’s life in Sanmaru

Wrong on the test. Right on three different days after.

  1. Test day

    Snap it

    Photograph the problem you missed. Your handwriting is erased, so you start from blank.

  2. Day 1

    First circle

    It comes back the next day. Solve it right, it gets a red circle.

  3. Day 4

    Second circle

    A few days later — right when it’s starting to fade.

  4. Day 11

    Mastered

    Three circles on three different days. It leaves your list, ready for test day.

Days shown as an example. Sanmaru picks each problem’s next day from how you did last time.

Everything a mistake notebook should do

Snap and erase

Tests, worksheets, workbook pages. Handwriting off, problem kept.

A few problems a day

About three at a time, spaced so each one comes back before you forget it.

Printable re-solve sheets

Clean worksheets of today’s problems, for pencil and paper.

Weekly parent report

What got fixed and what still needs work, once a week.

Your first circle is on Android soon.

One email when Android is ready. Unsubscribe anytime.

Join the Android waitlist