In high school math ,we usually had a stanupin the beginning of every lesson. Basically th entire class on their feet answering rapid fire questions from the teacher , usually some stuff that had been taught in the previous lesson. No calculator/notes just doing math in your head to get to sit down and start the class. Gnereally sucked when we were going through it , looking back though made digesting the material easier as you had to know, not just cram or hope for a calc or scrap paper to caluclate with.

So basically a oral pop quiz for math. i think could work well to complement homeworks by making sure the material as taught is actually inside the students heads.