I do not know why I suddenly thought about them when waking this morning, but several mnemonics came to mind. All of them I learned at school. Here are a few:

BODMAS : Brackets Of Division Multiplication Addition Substraction

Referring to the order in which arithmetic operations are carried out.

SOHCAHTOA : Sine=Opposite/Hypotenuse Cosine=Adjacent/Hypotenuse Tangent=Opposite/Adjacent

MR VAN STAMPED : First letters of French verbs that use etre in the perfect tense. Monter, Rester, Venir, Arriver … etc

ADOLPHUS HITLER : The vowels in Adolphus can follow a c cedilla – ç – in French, but those in Hitler cannot.

Although mnemonics are to aid the memory, I cannot recall any others. Can you?