The easiest way is to take the logarithm of the number, multiply it by the numerator of the power, divide by the denominator of the power and then take the anti-log. In your example, the log of 1823.5 is 3.2609058. Multiply this by 18=58.696304. Divide by 365=0.1608117. Now take anti-log=1.4481441 and that is your answer.