Final answer:
To write 5 x 10^-3 as an ordinary number, multiply 5 by 10 raised to the power of -3 and move the decimal point 3 places to the left. The result is 0.005.
Step-by-step explanation:
To write 5 x 10^-3 as an ordinary number, we need to multiply 5 by 10 raised to the power of -3. The exponent -3 indicates that the decimal point should move 3 places to the left.
Starting with 5, when we move the decimal point 3 places to the left, we get 0.005. So, 5 x 10^-3 is equivalent to 0.005.