The ones you have kept. Save any question on the site — on the problem itself, or beside the working when you print a worksheet — and add the ones your child brings home from school.
One your child got wrong. Type it out, or photograph it — either is enough.
When your child gets a question wrong, keep it. It stays on this device, and you can come back to it when they are ready to try it again.
Look for Save this question under any problem, and Save beside each answer on a worksheet’s working. Or add one of your own, above.
There is no account yet, so a bank stays in the browser it was made in. Save a copy here and bring it in on the other one — that is also how a sheet printed on a laptop gets marked on the phone that is actually on the table. Bringing one in adds to what is here; it never replaces it.
Kept in this browser. Nothing leaves it unless you send a question in to be drawn — so clearing this browser’s data clears the list, and a question kept on a phone will not appear on a laptop.