You have to sit for tashahud in the 2nd and 4th rakat, as usual. The rakah your payed with the Imam is your first rakah.

In duhr prayer I got only last 1 raka with the imam. Now when I have to complete more 3 rakah, so do I have to say tashahud in this 3 rakah? And if so then in which rakah I have to sit for tashahud?

Prayer | March 21, 2015 3:59 pm
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 When we are saying dhikr in prayer does it  essential to speak the words or its just enough when we move tongue without speaking and is this ruling come under fard salat prayer that recites  surah silently? [i mean reciting surah in silent pray, is it essential to utter the words when reciting surah?]
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I wanted to know how I can pray zuhar prayers when I am in the exam centre. The exam centre is really small. so i wont have a separate vacant place to pray.And by the time i finish my exam and reach home it will already be asar time. I dont know in which direction i will be seated… Is it still ok to pray with ishara/ imagine each step aand recite duas in my heart? I am really scared about this exam..and have written it a couple of times and wasnt able to get through, Could you advice dua or namaaz, which will help me make dua to clear the exam. .