Answer
$0.800307$
Work Step by Step
RECALL:
$10^{-1} = \dfrac{1}{10} = 0.1
\\10^{-2} = \dfrac{1}{10^2} = 0.01
\\10^{-3} = \dfrac{1}{10^3} = 0.001
\\10^{-4} =\dfrac{1}{10^4} = 0.0001
\\10^{-5} = \dfrac{1}{10^5} = 0.00001
\\10^{-6} = \dfrac{1}{10^6} = 0.000001$
Thus, the given expression is equivalent to:
$=(8 \times 0.1) + (3 \times 0.0001) + (7 \times 0.000001)
\\=0.8 + 0.0003 + 0.000007
\\=0.800307$