The expression $4+\frac{3}{10}+\frac{9}{1000}$ is equal to
(A) 4.12
(B) 4.309
(C) 4.039
(D) 4.012
(E) 4.39
Converting from fractions to decimals, $4+\frac{3}{10}+\frac{9}{1000}=4+0.3+0.009=4.309$.

ANSWER: (B)