Addition of Vectors

If $\overrightarrow{a}=2\hat{\mathrm{i}}+5\hat{\mathrm{j}}$ and $\overrightarrow{b}=2\hat{\mathrm{i}}-\hat{\mathrm{j}}$, then the unit vector along $\overrightarrow{a}+\overrightarrow{b}$ will be