Question: If one joins the Magrib Jamaat Salaah late, what is the method of completing the missed Rakaats?

Answers: A person who missed Rakaats  with the Jamaat is called a Masbuq. A masbuq will follow the Imam as per normal, except that in the last sitting, he will only reads at-Tahiyyat and then remain silent until the Imam makes Salaam. (The Masbuq will not read salawat and supplications.)

1) If the Masbuq missed one Rakaat, he will stand up after the Imam completes the Salaah, he will read Thanaa, Ta’awwuz, Tasmiya, Surah Fatiha and a Surah. After Ruku and Sajdah he will complete Salaah as normal. 

2) If two Rakaat were missed, then - when the Masbuq stands up to complete the missed Rakaats, he will read Thanaa, Ta’awwuz, Tasmiya, Surah Fatiha, a Surah, then go into Ruku and Sajdah, then he will then sit in Qa’idah and read at-Tahiyyat, after which he will stand up, read Surah Fatiha and a Surah and complete Salaah as normal.

3) If all three Rakaats were missed, the Masbuq will stand up after the Imaam makes Salaam and perform Salaah as if he is starting it from beginning.

والمسبوق  من سبقه الإمام بها أو ببعضها  وهو  منفرداً  فيما يقضيه - حتى  يثني  ويتعوذ  ويقرء ... ويقضي اول صلاته في حق قراءة -وآخرها  في تشهد ، فمدرك ركعة من غير فجر  يأتي بركعتين بفاتحة وسورة وتشهد بينهما   ( رد المحتار  ج٢ ص ٣٤٧) 

And Allah Ta’ala Knows Best

Yusuf Moosagie