Curiosity, with somewhere to go

Subtraction Fluency

One idea at a time. A whole collection within reach.

Follow a discovery trail ↗

Opening your progress…

Explored— / 496

Your breadth of coverage

Building recall—

Still becoming familiar

Reliable recall—

Recalled across time

Ready to revisit—

A little space helps the next check

What counts as reliable recall?

Three successful recalls, each at least 24 hours after the previous counted recall, with no miss since. Repeating immediately won’t move this count. A miss returns the card to learning. Due cards remain part of your history and need another check.

0 cards also have three spaced, unaided test recalls. Study ratings are your own assessment. These are learning signals, not a guarantee of exam performance or real-world expertise. Older progress counts toward coverage; spaced evidence starts with this feature.

Your next useful step

There’s more here for you.

Choose a brief visit or settle in. You can leave and resume a round.

Opening your review options…Study the whole collection →Check unaided recall →

See the whole picture

Build it chapter by chapter.

The things that made you look twice

Your discoveries

When a reveal surprises you, save it with “That surprised me.” It will be waiting here.

A moment to reflect · optional

What did this learning session leave you with? This reflection stays on your device and can be included in your downloaded learning record.

Your learning data

Keep a copy of your progress, discoveries and written thinking. These controls work even before your first completed round.