The Library uses the Library of Congress (LC) Classification System to assign call numbers. You maybe more familar with the Dewey Decimal system used in public and school libraries, so this system will look a little different.
In the LC system the first 2-3 lines in the call number use a mix of letters and numbers to indicate the subject area in which the book is assigned.
The main call number used for Mathematics is QA. The numbers that come after QA each correspond to a subheading of the Mathematics subject area.
QA Mathematics
QA 1-43 General
QA 47-59 Tables
QA 71-90 Instruments and machines
QA 101-145 Elementary mathematics. Arithmetic
QA 150-272 Algebra
QA 273-280 Probabilities. Mathematical statistics
QA 299-433 Analysis
QA 440-699 Geometry. Trigonometry. Topology
QA 801-939 Analytic mechanics