Fasting three days each month as a substitution for fasting Mondays and Thursdays

Question: Is observing Sawm (Fast) on the White Days sufficient for the Sawm of Monday and Thursday as well?

Answer: The Sawm of the White Days i.e. (13th, 14th, and 15th of every Hijree month) and the weekly Sawm of Mondays and Thursdays is an independent legitimate form of `Ibaadah (worship). Whichever sort of Sawm someone intends, they are rewarded for it... read more here.