premise: how can I plant a broken piece of cactus?
hypothesis: Check the broken end of the cactus. ...    Set the cactus piece aside allowing the cut end to callous over. ...    Fill a pot with cactus spikes    Insert the calloused end into the soil approximately 1 to 2 inches deep. ...    Place the pot in a warm, sunny window.    Water the soil thoroughly, two to four weeks later.