4.9+15.21/1.9 estimate

$$\\4.9+15.21/1.9\\ \approx 5+15/2\\ \approx 5+7.5\\ \approx 12.5$$

exact answer

$${\mathtt{4.9}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{15.21}}}{{\mathtt{1.9}}}} = {\frac{{\mathtt{1\,226}}}{{\mathtt{95}}}} = {\mathtt{12.905\: \!263\: \!157\: \!894\: \!736\: \!8}}$$

Well the estimate is fairly close   :)

 4.9+15.21/1.9