The answer is 1/250
Rewrite the decimal number as a fraction with 1 in the denominator
0.004=0.0041
Multiply to remove 3 decimal places. Here, you multiply top and bottom by 103 = 1000
0.0041×10001000=41000
Find the Greatest Common Factor (GCF) of 4 and 1000, if it exists, and reduce the fraction by dividing both numerator and denominator by GCF = 4,
4÷41000÷4=1250
Therefore
X=1250
In conclusion,
0.004=1/250