2/5+4/10=

To add the fractions \( \frac{2}{5} \) and \( \frac{4}{10} \), we first need a common denominator.

The denominator of \( \frac{2}{5} \) is 5, and the denominator of \( \frac{4}{10} \) is 10. The least common multiple (LCM) of 5 and 10 is 10.

Next, we convert \( \frac{2}{5} \) to an equivalent fraction with a denominator of 10:

\[ \frac{2}{5} = \frac{2 \times 2}{5 \times 2} = \frac{4}{10} \]

Now we can add the two fractions:

\[ \frac{4}{10} + \frac{4}{10} = \frac{4 + 4}{10} = \frac{8}{10} \]

Finally, we can simplify \( \frac{8}{10} \):

\[ \frac{8}{10} = \frac{8 \div 2}{10 \div 2} = \frac{4}{5} \]

So, \( \frac{2}{5} + \frac{4}{10} = \frac{4}{5} \).