High school mathematics arc system problem.
In 24 hours, the minute hand will walk 24 times and the hour hand will walk 2 times, so they overlap 24-2=22 times. Think of it this way: at 0: 00, the two stitches overlap once, but within an hour from 0: 00 to 1: 00, the two stitches will not overlap. From 1 point to 2 o'clock, 2 o'clock to 3 o'clock ... until 1 1: 00 to 12: 00, it will overlap once. But from 12: 00 to 13: 00, the two stitches will not coincide. After that, it will overlap every hour. So there are two hours a day without overlapping, and the number of overlapping stitches is 24-2=22.