I have a great concern regarding Qadha salaah, I have years of qadha salahs to make up, I started reading 5 times prayer recently, please help me because I don’t understand how to make them up, how do I work it out? I want to make them before I die, but I can’t remember the amount, so what is the method in completing them?
In the name of Allah, the Most Gracious, the Most Merciful.
Assalamualaikum Warahmatullahi Wabarakatuh
Alhamdullilah, It is very encouraging that you have taken up the initiative of your great concern and sought Advice from the Ulama. We make Dua to Allah Ta’ala that he grants you Istiqamat (steadfastness) and He makes it easy for you to fulfil all your Qada Salaat.
It is not necessary for a person who has Qada (missed) Salaat to remember the exact date when making up for the missed Salaat. Ulama suggest that if a person has several years of Qada Salaat and he does not remember the number of Salaat he missed, neither does he remember the time of the Salaats, then he should adopt the following method in completing his missed Salaats:
1) It will suffice for a person to merely say in his intention that this is a Qada of the first (or last) Salaat he missed. Example, he should make intention that he is making Qada of the first (or last) Dhuhr Salaat which he missed. Once the Qada of this Salaat is complete, the second Salaat which he missed will take the place of the first, and likewise when that is completed the third will now be the first; hence, on every prayer he can merely suffice by saying ‘Ya Allah, I am making the Qada of the first (or last) prayer I missed.
2) Instead of reading Nawaafil Salaat a person should pay more attention on his Qada Salaat first.
3. A person should read at least one Qada Salaat with every Fard Salaat, by adopting this method Inshallah a time would come when all his Qada Salaat would be fulfilled.
And Allah Ta’ala knows best
Mufti Luqman Hansrot
من لا يدري كمية الفوائت يعمل بأكبر رأيه فإن لم يكن له رأي يقض حتى يتيقن أنه لم يبق عليه شيء
(حاشية الطحطاوى ,ص447)
 كثرت الفوائت نوى أول ظهر عليه أو آخره
(الدر المختار ج2 , سعيد,ص76)
وإذا كثرت الفوائت يحتاج لتعيين كل صلاة فإن أراد تسهيل الأمر عليه نوى أول ظهر عليه أو آخره
(نور الإيضاح – ص 100)
 وأما النفل فقال في المضمرات : الاشتغال بقضاء الفوائت أولى وأهم من النوافل إلا سنن المفروضة
(رد المحتار, سعيد ج2 ,ص74)
 (Fataawa Mahmoodiyah, Farooqiaya, Vol 7, Pg364)