We use standard form to write a huge number in a 'small' form. In this case:
[tex] 45 000 [/tex] becomes [tex] 4.5 \cdot 10000 [/tex] and finally [tex] 4.5 \cdot 10^{5} [/tex]
[tex] 10^{5} [/tex], because we move the decimal point 5 places to the left.
