Final answer:
The expression $2\cdot 10^2 + 3\cdot 10^{-3}$ is converted to 200.003 when written as a decimal.
Step-by-step explanation:
To write $2\cdot 10^2 + 3\cdot 10^{-3}$ as a decimal, we need to understand how to work with exponents and the base of 10. $2\cdot 10^2$ means 2 times 10 squared, which is equal to 2 times 100 or 200. On the other hand, $3\cdot 10^{-3}$ means 3 times 10 to the negative third power, which is equal to 3 times 0.001 or 0.003. Adding these two values together, we get a final answer of 200.003.