Question

Estimates show that there are 1.4*10^8 pet fish and 9.4*10^6 pet reptiles in the United States.

Answer 1

$\bf \stackrel{fish}{1.4\times 10^8}~~+~~\stackrel{reptiles}{9.4\times 10^6} \\\\\\ \stackrel{fish}{140000000}~~+~~\stackrel{reptiles}{9400000}\implies \begin{array}{rrrrllll} 140000000\\ +9400000\\ \text{\textemdash\textemdash\textemdash\textemdash\textemdash}\\ 149400000 \end{array}\implies 1.494\times 10^8$