100:50 60:10 7*2+7*8 4*6+6*6 30*3-10*4 20*4+60:3 8*9-48 56-7*8

Here are the solutions to each of your calculations:

1. 100:50 = 100 ÷ 50 = 2
2. 60:10 = 60 ÷ 10 = 6
3. 72 + 78 = 14 + 56 = 70
4. 46 + 66 = 24 + 36 = 60
5. 303 - 104 = 90 - 40 = 50
6. 20*4 + 60:3 = 80 + 20 = 100
7. 8*9 - 48 = 72 - 48 = 24
8. 56 - 7*8 = 56 - 56 = 0

If you have more questions or need further explanation on any topic, feel free to ask!