Consider the given statement,0.
The equivalent mathematical expression will be,

Consider that a decimal number can be converted into a fraction using the following steps;
i) Identify the number of digits after the decimal in the number. Suppose there are 'x' digits after decimal.
ii) Then remove the decimal and put a 1 in the denominator, and then put as many zeroes as there were number of digits after the decimal i.e. x .
Now, apply this algorithm to the expression,

It is known that leading zeroes of a number have no significance. So remove the leading zeroes, and simplify the expression as follows,

Now, apply the above steps to convert the fraction to deimal form,

Thus, the 0.0405 divided by 0.9 gives 0.045