Question: Add. Write your answer in scientific notation.
$7.9\times10^{4}+2\times10^{5}$
1. **State the problem:** Add the numbers $7.9\times10^{4}$ and $2\times10^{5}$ and write the answer in scientific notation.
2. **Recall the rule:** To add numbers in scientific notation, they must have the same exponent.
3. **Rewrite both numbers with the same exponent:**
$$7.9\times10^{4} = 0.79\times10^{5}$$
4. **Add the coefficients:**
$$0.79 + 2 = 2.79$$
5. **Write the sum in scientific notation:**
$$2.79\times10^{5}$$
6. **Final answer:**
$$2.79\times10^{5}$$