5. 9*4, 8*4, 7*4, 32:4, 14:7, 24:6, 20:4, 36:9, 28:4, 42+(20-8), 50-(17-9), 70-(38+7)

1. 9*4 = 36, 8*4 = 32, 7*4 = 28.
2. 32:4 = 8, 14:7 = 2, 24:6 = 4.
3. 20:4 = 5, 36:9 = 4, 28:4 = 7.
4. 42+(20-8) = 42+12 = 54.
5. 50-(17-9) = 50-8 = 42.
6. 70-(38+7) = 70-45 = 25.