To express \( 0.000456 \) in scientific notation, you move the decimal point to the right until you have a number between 1 and 10.
In this case, you would move the decimal point 4 places to the right, which gives you \( 4.56 \). Since you moved the decimal to the right, you will use a negative exponent.
Thus, \( 0.000456 \) can be written in scientific notation as:
\[ 4.56 \times 10^{-4} \]