What is 66.5 divided by 3.5

66.5 divided by 3.5 is 19.

19 because when dividing decimals you can't have a decimal in the divisor (3.5) some you move the decimal to the right but what you do to the divisor you also have to do to the dividend (66.5) so you move the decimal in the dividend to the right also. Then the problem you have is 665 divided by 35 and you can use simple log division to solve it.