What is the relationship with 0.04 and 0.004

Well,

You could say that 0.04 is greater than 0.004.
0.04 > 0.004

You could be more specific and say how much greater 0.04 is compared to 0.004.
0.04 = 10(0.004)

You can also make general conclusions about the two numbers.

"0.04 and 0.004 both are less than 1."

"Both numbers have fractional forms that can be simplified."

"Both numbers have a zero to the left of the decimal point."

And so on and on.