You're close! It's important to remember the correct exponent.

Here's why it's important:

* Scientific Notation: The way we express very large or very small numbers like the mass of a proton is called scientific notation. It uses a base number (in this case, 1.67) multiplied by a power of 10 (in this case, 10^-27).

* Order of Magnitude: The exponent tells us the order of magnitude of the number. A negative exponent means the number is very small. 10^-27 is much smaller than 10^-18, making a huge difference in the size of the proton's mass.