Operations with scientific notation

Question

Perform the indicated operation. Each final answer must be written in scientific notation.
1. (2.34*10^5)*(-4*10^-8)
2. (4*10^3)*(4.5*10^-3)
3. (5*10^5)*(4.3*10^2)

Answer 1

multiply the numbers and add the exponents. The answer has to be arranged so the number part is between 1 and 10.

for example your number 3.

(5*10^5)*(4.3*10^2)

= 5 * 4.3 * 10^(5+2)

= 21.5 * 10^7 but 21.5 = 2.15*10^1
so
2.15 * 10^1 * 10^7

= 2.15 * 10^8

Answer 2

Thanks.