When putting numbers into scientific notation, always put the decimal after the ones place. In this case, you would put the decimal after 4 and before 5 (in between). From there, you count how many decimal places you moved in order to change it into that form.
0.45013 would change to 4.5013 and you would have to multiply it by 10 to the negative power of 1 (you're only moving back one place).
4.5013 x 10^-1
Hope this helps :)