"To apply the math" means to use mathematical concepts, calculations, or principles to solve a problem, make a decision, or find a solution in a particular situation. Full definition
The floor plan provides an authentic scenario for applying math skills they've been introduced to in the first few months of school. (edutopia.org)
Set on pursuing a Ph.D. since age 5, she found a perfect marriage for her skills and interests at the intersection of applied math and atmospheric chemistry. (seas.harvard.edu)
He focused on applied math, constructing equations to examine how many dimensions of variables certain systems could handle, and designing configurations to handle more. (discovermagazine.com)