Ya cool, it is very easy to remember.
1947 is the year, when India got indenpendence. Add or subtract it with certain numbers.
For 1941, subtract it by 6.
You can relate with other years, or the famous incidents.
Another is by using the alphabets.
1=a,9=i,4=d,1=a. Therefore, aida.
Thus, you can also use the alphabets in the reverse manner.