according to https://support.microsoft.com/en-us/office/ceiling-function-0a5cd7c8-0720-4f0a-bd2c-c943e510899f Excel rounds negative numbers differently:
'If number is negative, and significance is **negative**, the value is rounded **down**, away from zero.
If number is negative, and significance is **positive**, the value is rounded **up** towards zero.'
That should give '=ceiling(-8,3)' -> -6, the tests in mathfuns.xls do not test this situation, all gnumeric versions I have tested calculate '#NUM!'.
Did I miss something or should gnumeric be improved?
