Salaah

Q: I have short term memory problem when I am praying salah. Sometimes I don't know how many rakat (rakah) I did, what shall I do then? I always don't know how many sajdah I did. If I did 1 or 2 sajdahs I don't remember. If I do more than 2 sajdah or do less than 2 sajdah would my salah be valid? I don't know if the cause of my problem is shaytaan. If I don't know how many rakaats and sajdah I did, what can I do? If I don't know, can I just do 1 more rakat or 1 more sajdah?​

Q: In Kitaab al-Asl of Imaam Muhammad it states that according to Abu Hanifa the imaam should not say "Rabbanaa lakal hamd". But in the same book Imaam Muhammad ask Abu Hanifa whether the Imaam should recite basmalah, amin and Allaahumma rabbanaa lakal hamd silenty and Abu Hanifa says yes. Why this contradiction?

Q: I have a problem reciting a certain part of the Tahiyyaat in Tashahhud. The part is: "...wa alaa ibadillaah'is salihin.." I have trouble pronouncing the last letter "n" out. Is it also permissible to read that part as: "...wa alaa ibaadillaah as salihin.." ? Thus "ibaadillaah" and "as" seperately, instead of connected as "ibaadillaah`is"?

Q: I have deep doubts regarding the authenticity of witr salaah of the Hanafi Madhab. I have asked a Sheikh and he told me not to read in that manner. Can you mention to me few authentic Hadeeth regarding this issue. 

Q: Is it permissible to read namaaz behind an imam who's garments are below his ankles?

Q:

1. A person in the state of Wudhu drinks some juice/fizzy drink/tea/coffee etc. Is it necessary to gargle the mouth before performing Salaah?
2. A person in the state of Wudhu chews some bubblegum and thereafter spits it out. The taste still lingers in the mouth.Is it  necessary to gargle the mouth before performing Salaah? The bubblegum was chewed in order to remove odour from the mouth.

Q: If a Hanafi follows a Shafi'ee imam whose salat is valid according to the Shafi'ee madhab but not the Hanafi mazhab (e.g. when doing masah of the head in wudu, the Imam did masah of just 3 straws of hair), will the salaat of the Hanafi follower be valid?

Q: Assuming in the first rakaat of witr, one recites Surah Lahab and Surah Ikhlaas in the second rakaat. Is it necessary to make sajda sahu as only Surah Falak or Surah Naas can be recited in the third rakaat but these Surahs are longer than Surah Ikhlaas. Likewise, in any other namaaz, if one recited a Surah in the second rakaat that is slightly or much longer than the surah recited in the first rakaat, what is the ruling?

Q: Is there a Hadith which says a person would wait 40 years if he new the punishment for walking in front of a musalli (a person praying salah)?

Q: Can we make qadha of witr Salaah also?