$\frac{1}{10}+\frac{2}{20}+\frac{3}{30} =$
$\text{(A)}\ .1 \qquad \text{(B)}\ .123 \qquad \text{(C)}\ .2 \qquad \text{(D)}\ .3 \qquad \text{(E)}\ .6$
Each of the [fractions](https://artofproblemsolving.com/wiki/index.php/Fraction) simplify to $\frac{1}{10}$, so this [sum](https://artofproblemsolving.com/wiki/index.php/Sum) is
\begin{align*} \frac{1}{10}+\frac{1}{10}+\frac{1}{10} &= \frac{3}{10} \\ &= .3 \rightarrow \boxed{\text{D}} \end{align*}