Steve spends 24/3 = <<24/3=8>>8 hours sleeping.
He spends 24/6 = <<24/6=4>>4 hours in school.
He spends 24/12 = <<24/12=2>>2 hours making assignments.
He spends 8 + 4 + 2 = <<8+4+2=14>>14 hours either sleeping, going to school, or making assignments.
Hence, Steve spends 24 - 14 = <<24-14=10>>10 hours with his family.
#### 10