Cambridge AssessmentNotation ListFor Cambridge International MathematicsQualificationsFor use from 2020Notation List for Cambridge International Mathematics Qualifications(For use from 2020)Mathematical notationExaminations for CIE syllabuses may use relevant notation from the following list.1 Set notationis an element ofis not an element of{x:}the set of all x such that...n(A)the number of elements in set A0the empty setthe universal setUthe universal set (for 0607 IGCSE Intemational Mathematics)the complement of the set ANthe set of natural numbers,(1,2,3,...}the set of integers,{0,±l,±2，±3，.}the set of rational numbers,the set of real numbersthe set of complex numbersthe ordered pair x,y드is a subset ofis a proper subset ofUunionintersectionthe closed interval{x∈R:a≤x≤b}[a,b)the interval{x∈R:a≤x