FIND A FRACTION SUCH THAT: IF YOU ADD 2 TO THE NUMERATOR, IT BECOMES EQUIVALENT TO 0.5; AND IF YOU ADD 4 TO THE DENOMINATOR, IT BECOMES EQUIVALENT TO 0.1.
(n + 2)/d = 0.5
n/(d+4) = 0.1
n = 0.5 d - 2
n = 0.1 d + 0.4
0.4 d = 2.4
d = 6
(n+2)/6 = 0.5
n+2 = 3
n = 1
The original number is n/d = 1/6