Lonneke van Krimpen was studying for her final exam in geometry at the secondary school level and noticed something was off. She did a practice question from a 2014 exam and noticed that her protractor was wrong. A friend of hers apparently had the same issue and so they told HEMA that their protractors were badly made.
HEMA was happy to be told this especially before the entire country takes their final exams. They said they have pulled their protractors from the shelves, flagged their inventory, and even blocked any sales of them at the cash register. As well, anyone with a bad instrument can trade it in for a good one.
The specific problem is that between the 50 and 60 there are 11 spaces, and between 60 and 70 there are 10, when in both cases there should be nine.