1.
3.6*10^4÷(1.8*10^3)
=(3.6÷1.8)*(10^4÷10^3)
=2*10
=20本
2.
10^(7-1)÷10^(5-1)
=10^6÷10^4
=10^(6-4)
=10^2
=100倍