What is the best ways to assess students in math class?

 

I find that different teachers have different methods of assessing students in math. Some of them use the old fashion way and others use new strategies. One of my associates used the tests marks to assess students while the other used the application, thinking and communication methods to assess her students. I find it too difficult to assess students in math and wondering what is the best way to assess my students? I used both in my placements but need to know more of what is the best for my students. Some methods sounds good but when it come to marking, it is not that fun anymore. What do you think?