10^-4 = 1/10^4
100^7/10^7 = 10^(14)/10^7 = 10^7
10^-4*100^7/10^7 = 1/10^4 * 10^7 = 10^3
100^-4 = 1/10^8
10^-4*100^7/10^7*100^-4 = 10^3 * 1/10^8 = 10^(-5)
10^-4 = 1/10^4
100^7/10^7 = 10^(14)/10^7 = 10^7
10^-4*100^7/10^7 = 1/10^4 * 10^7 = 10^3
100^-4 = 1/10^8
10^-4*100^7/10^7*100^-4 = 10^3 * 1/10^8 = 10^(-5)