A/Alaikum, I was told that the Azkar that are offered after the obligatory prayers, i.e. Subhanallah, Alhamdulillah, Allahu Akbar [33 times each]; could also be offered 10, 15 or 25 times each. Kindly guide me the Ahadith that support this. Ma'assalam,

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

As regards the evidence of saying "Subhaanallaah", "Al-hamdu lillaah" and "Allaahu Akbar" ten times each after the obligatory prayer, the Prophet said: ''There are two characteristics which, if one observes, will cause him to enter Paradise. They are very easy actions, but very few people perform them, it is to say after concluding every obligatory prayer "Subhaanallaah" ten times, "Al-hamdu lillaah" ten times, and "Allaahu Akbar" ten times….'' 

It is also permissible to say "Subhaanallaah" 25 times, "Al-hamdu lillaah" 25 times, and "Allaahu Akbar" 25 times, and "Laa ilaaha illallaah" 25 times, and this makes 100 times, and this is reported by An-Nisaa'i and narrated by Ibn 'Umar from the Prophet .

Therefore, it is recommended for a praying person to say any of these kinds of the mention of Allaah, and if he alternates between them all he will say all the confirmed forms of mentioning of Allaah.

As regards saying “Subhaanallaah” 15 times, “Al-hamdu lillaah” 15 times, and “Laa ilaaha illallaah” 15 times, then, as far as we know, it is not reported in any Prophetic narration.

Allaah Knows best.