1 making money 2 Our teacher also said that many theories of mathematics were discovered a long time ago, and it may take hundreds of years for these laws or theories to be put into practice, which also requires human development, that is, applying mathematics to turn pure mathematics into practical mathematics. 3 research indifference. This may be known to everyone, such as detection, armed detection, launching anything, using mathematics. Of course, the most important, frequent or common thing for us now is to calculate it and spend it on the usual small increase, calculation, food purchase and shopping in our lives.