## Thinking Mathematically (6th Edition)

$30,700.05809$
RECALL: $10^{4} = 10,000 \\10^{2} = 100 \\10^{-2} = \dfrac{1}{10^2} = 0.01 \\10^{-3} = \dfrac{1}{10^3} = 0.001 \\10^{-5} =\dfrac{1}{10^5} = 0.00001$ Thus, the given expression is equivalent to: $=(3 \times 10,000) + (7 \times 100) +(5 \times 0.01) + (8 \times 0.001)+(9 \times 0.00001) \\=30,000 + 700 + 0.05 + 0.008 + 0.00009 \\=30,700.05809$