To find the decimal form of a percentage, you divide by 100. If you have a decimal, then to divide by 100 just move the decimal 2 places to the left.
0.4% = .004
Now to turn it into a fraction, just read the place value...
four one thousandths = 4/1000
Now reduce... 4/1000 = 2/500 = 1/250
The simplest form of 0.4% as a fraction is... 1/250
