A question comes through conversion, gets checked against the answer key on your worksheet, and the two don't agree. Our answer says 3/8. Your key says 3/4. Before you see anything else, the item is flagged red in the approval queue with the page it came from beside it.
More often than not, it's the worksheet.
How the mismatch is found
Every question converted from your material is checked against whatever answer your material gives for it. Where the worksheet has a key, the answer we generate has to match it. If it does, the item goes into the queue as clean. If it doesn't, it goes in flagged, and it stays flagged until you resolve it.
Nothing flagged can be published. Nothing at all can be published until you've approved it. So the mismatch never reaches a student. It reaches you, with the question, both answers, and one click to the original page.
That click is the important part. You're not looking at a question in isolation and guessing which answer to believe. You're looking at your worksheet, the one you've been handing out, and working the question yourself with the page in front of you.
Why it's usually the worksheet
Because the worksheet has been wrong for years and nobody was checking.
Keys get written in a hurry at the end of a long afternoon. A question gets edited, the numbers change, and the key doesn't. A worksheet gets copied from an older version and inherits the older version's mistake. A tutor marks against the key, trusts the key, marks a correct student wrong, and the student assumes they're bad at fractions.
None of this is careless. It's what happens to any document that's been in use for a decade with nobody paid to audit it. Conversion is the first time every question on every page has been worked through independently and compared with the answer beside it, and it finds things.
Sometimes it's the conversion that's wrong. A skewed scan, a fraction that came through as three characters in the wrong order, a diagram that got separated from its question. When that's the case you'll see it from the page, because the original is right there and the converted question isn't. Tell us and it's fixed that day. The upload and convert page covers what makes a scan convert cleanly in the first place, so this case stays rare.
Finding it is a gift
Here's the reframe, because the first reaction to a red flag is usually irritation.
That error was live. It's been on the sheet that goes home every Tuesday. Students have been marked wrong on it, or marked right for the wrong answer, and a few of them have carried a misunderstanding out of your room because the key told them to. You didn't know, because the only person who'd have caught it was you, at 10pm, marking fast against the same key.
Now you know, and it cost you a click. The question gets fixed, the fix publishes, and every student who does that set from here on gets the right answer marked right. If you want to go further, the flagged item tells you which page of which worksheet, so you can fix the paper version too.
If you go through a first batch, expect a handful of these. It's not a comment on the material. It's a comment on how long it's been since anyone checked, which for most centres is never.
Fixing it in the queue
Resolving a flag is a small job. You can edit the question or the answer in place. Change the wording, swap a number, correct a typo that was in the original. Your edit is what publishes, and the item keeps its link to the original page so there's always a record of what it came from and what you changed.
Or bin it, if the question wasn't worth keeping. Or approve our answer over the key, if you've worked it and agree. Or approve the key, if we got it wrong. The choice is yours on every item, and once you've made it the flag clears and the batch moves on.
The approve before publish page has the queue in full. Clean batches can be approved in one click. Flagged items can't, and that's deliberate.
"It came from your worksheet, here's the page"
This is the sentence the whole thing rests on. When a parent asks why a question was worded a certain way, or why their child was marked wrong on it, the answer is on your screen: the question, the worksheet it came from, the page, and whether you changed it.
That's what grounding means in practice. Every item traces to a page. Anything that can't be traced is rejected before you see it. So a flagged answer is never a mystery about where a number came from. It's a disagreement between your page and our reading of it, and you're the one who settles it.
A platform that supplies its own material can't say that sentence, because the material isn't yours. A general chatbot can't say it, because there's no page. It's the strongest position a platform can put a centre in, and a red flag in the queue is that position doing its job.
This week
Pick one worksheet you've used for years and work the answer key yourself, cold, without looking at what you wrote last time. You'll probably find at least one thing. If you'd rather have it checked for you, send it through convert my worksheets and see what comes back flagged.