1)(2.3x10^2)(4.5x10^-7)= 1.035x10^-6
2) 4.8x10^2/1.2x10^5= 4.8x10^-3
for dividing use this equation:
n*10^a / n*10^b = n/m * 10^a-b
for multiplying use this equation:
(n x 10a) • (m x 10b) = (n · m) x 10a+b
1)(n · m) x 10a+b :
(2.3 * 4.5) x 10(2+(-7))
(10.35) x 10(-5)
Therefore it should be 10.35x10^-5