Takapuna Grammar student Maia Brown said she could hear other students crying in the exam hall as they took the test.
The 15-year-old, who is in an accelerant maths class and usually gets merit and excellence results, said she did five mock exams before the test, but when she read the first question on the official test she knew she was "doomed".
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"Most of it was things I hadn't seen, things we hadn't been taught," she said.
Many of the questions were vaguely-worded as well.
She was able to answer some achieved-level questions but "apart from that it was complete chaos".