Example 2. Calculate $7.38 \times 10^{3}+2.26 \times 10^{4}$ (all are approximate numbers).
\begin{array}{l}\text { Solve } 7.38 \times 10^{3}+2.26 \times 10^{4} \\ =0.738 \times 10^{4}+2.26 \times 10^{4} \approx 3.00 \times 10^{4} .\end{array}