Answer:
[tex]10^{4} * 10^{3}=(10*10*10*10)(10*10*10) = 10^{7}\\\\10^{4}*10^{4}=(10*10*10*10)(10*10*10*10) = 10^8\\\\(10*10*10)(10*10*10*10*10)=10^3*10^5=10^8\\[/tex]
[tex]10^{18}*10^{23}=[/tex] (10 x 10 18 times)(10 x 10 23 times) [tex]=10^{41}[/tex]
just as a note: when you multiply numbers with exponents and they both have the same base, all you have to do is add the exponents.
Ex: [tex]10^{5}*10^{4}=10^{5+4}=10^{9}[/tex]
