intuitive, experiential, and oral but this year Tim wanted N. to add some written problems to his math repertoire. For example, the other day Tim asked N. to write out all the ways to make 8 that he could think of.
So, several days a week they've been doing this more traditional math practice. Tim wants to insure that N. develops some test-taking skills by practicing solving math problems in their most conventional form. And as I wrote earlier this year, cognitive research shows that tests and quizzes are effective in reinforcing knowledge over the long term. I'd guess that the act of writing the entire problem out, not just the answer, also reinforces learning.