1. **State the problem:** Calculate the value of $2.3 \times 10^{-3} + 6.8 \times 10^{-4}$ and express the answer in standard form. 2. **Recall the rule:** To add numbers in scientific notation, they must have the same power of 10. 3. **Rewrite both terms with the same exponent:** $$2.3 \times 10^{-3} = 2.3 \times 10^{-3}$$ $$6.8 \times 10^{-4} = 0.68 \times 10^{-3}$$ 4. **Add the coefficients:** $$2.3 + 0.68 = 2.98$$ 5. **Combine the sum with the common power of 10:** $$2.98 \times 10^{-3}$$ 6. **Final answer:** The sum in standard form is $$\boxed{2.98 \times 10^{-3}}$$