Is there a reward for fasting the remaining days of Dhul-Hijjah for one who missed fasting its first days?

It is not a prerequisite to fast all ten days of Dhul-Hijjah to attain the reward, for whoever fasts some of the days will receive the reward for what they fasted. Fasting and other good deeds during these virtuous days are recommended, based on the Prophet's (peace and blessings be upon him) saying: "There are no days in which righteous deeds are more beloved to Allah than these days—meaning the ten days. They said: 'O Messenger of Allah, not even Jihad in the way of Allah?' He said: 'Not even Jihad in the way of Allah, except for a man who went out with his self and his wealth and did not return with anything of that.'"