| Subject | English | Zulu |
| comp., MS | not a number | akusiyo inamba (A value that represents the result of an invalid calculation) |
| comp., MS | not applicable | akutholakali (Pertaining to something for which an answer is not available or appropriate) |
| comp., MS | not valid | akulungile (Erroneous or unrecognizable because of a flaw in reasoning or an error in input. Invalid results, for example, might occur if the logic in a program is faulty) |