Recently had cancer removed and now set to have chemo. If all the cancer was removed how many times would I have to have treatment?

Depends. On the type of cancer, stage, and other factors. Talk to your doctor. Chemo is given because even if all the cancer the surgeon could "see" was removed there still can be a high chance of microscopic cancer cells being present somewhere in the body. The only way to tell for certain no cells are left is "the test of time, " meaning the cancer does not recur.