x ∈X : x is element of X X∋ x : X contains x A⊂B : A is contained in B, A is a subset of B A⊃B : A contains B A∪B : A union B, A cup B, union of A and B A∩B : A intersection B, A cap B, intersection A and B A c : complement of A ( ) : parentheses { } : braces [ ] : brackets 0.12 : zero-point-one-two 12.34 : twelve point three four therefore 12% : twelve percent 3/25 : three twenty-fifths 1/30 : one thirtieth 9/75 : nine seventy-fifths 6/50 : six fiftieths 12/100 : twelve hundredths 24/200 : twenty-four two-hundredths 1/2 : one half, one over two 3/2 : three halves, three over two 1/3 : one third, one over three 2/3 : two thirds, two over three 1/21 : one twenty-first, one over twenty one 2/21 : two twenty-firsts, two over twenty one 3/22 : three twenty-seconds, three over twenty two 2 2/3 : two and two third ∴ : therefore ±a : plus or minus a a 2 : a square [squared] a 3 : a cube [squared] a 4 : a to the four [fourth(power)] a n : a to the n [n th(power)] a=b : a equals [is equal