Can I apply to mathematics with AAAB

my Final UCAS predictions are AAAB in Economics, Physics, Math and Further-math
parents are forcing me to look ambitious so I am really worries I can't get into any of my UCAS choices, they are currently Oxford, Imperial, UCL, KCL and manchester (I know Oxford Imperial are just delusional dreams, but is it possible for me to apply for UCL at all?)

Oxford and Imperial will reject you (they require A*s in maths and Further maths, and A's in all other subject)
UCL will reject you (at a minimum they require A*A* single and further, OR A*A in Mathematics and Further Mathematics, in any order, and a 2 in any STEP Paper or a Distinction in the Mathematics AEA)
Etc.
I don't mean to be patronising, but you have to play the cards you have been dealt - which (unless in the case of some exceptional admission test results and extenuating circumstances) is insufficient for any of the universities you have listed there.
Remember that they are the top institutions in the world with people frequently applying with 3, 4, 5 sets of full A* and high admission test results. Your application is unlikely to make it very far with any of the above listed universities, especially with a B in FM when you want to apply for Mathematics.
I highly recommend talking to your parents about this. You only get 5 applications, so using them on universities which you have a very low chance of getting into is unwise. Having one or two at most is fine, maybe KCL or Manchester as your most ambitious applications, but otherwise the rest should match up more closely with your academic profile.
Also remember, at the end of the day you will be spending 3-4 years of your life here. Even if you got into Oxford, Imperial or UCL, you need to consider whether the pacing will actually be right for you. Many talented 'ace' students shatter under these universities, so it is not something to take lightly.
Good luck whatever you chose.

Oxford, Imperial, UCL, KCL and manchester
Too many high-risk choices - especially the first 4. These are all mega-competitive Unis for Maths, and every year thousands (yes, thousands) of applicants who meet or even exceed, the entry requirements, are rejected. This means you could easily end up with just an offer from Manchester - or no offer at all. You haven't stated the entry requirements for these choices - but if any of these choices are asking for an A*, then you are certain to get a rejection
Assuming you meet the entry requirements, applying for Oxford and one of the London choices before the October deadline would be a a sensible initial application. You may get responses before January, and could then add 3 informed choices ('strategic') before the Jan deadline to maximise your chances of offers.
Less competitive AAA offers for Maths include :
Undergraduate - Lancaster University
Courses | Mathematical Sciences | Loughborough University (lboro.ac.uk)
And a sensible AAB choice would be Sheffield or Southampton, or for a ABB Insurance, Liverpool or Cardiff.

my Final UCAS predictions are AAAB in Economics, Physics, Math and Further-math
parents are forcing me to look ambitious so I am really worries I can't get into any of my UCAS choices, they are currently Oxford, Imperial, UCL, KCL and manchester (I know Oxford Imperial are just delusional dreams, but is it possible for me to apply for UCL at all?)

I'm intrigued as to what your parents argument actually is. Have they seen the entry requirements and just ignored them?
A couple of suggestions....
Bang in a couple of "aspirational" choices, then when you get rejected fill in the rest with more realistic options.
Have a look at foundation courses. I know Manchester offer one.

Just average Asian parents never heard of universities other than Oxbridge. all rest of them are considered to be equally ****. Although themselves haven't been to higher education but they did support me to come abroad to read in an international school, they demand was simply if I don't even try Oxford there is no point for me to continue my highschool education...

Just average Asian parents never heard of universities other than Oxbridge. all rest of them are considered to be equally ****. Although themselves haven't been to higher education but they did support me to come abroad to read in an international school, they demand was simply if I don't even try Oxford there is no point for me to continue my highschool education...

Just average Asian parents never heard of universities other than Oxbridge. all rest of them are considered to be equally ****. Although themselves haven't been to higher education but they did support me to come abroad to read in an international school, they demand was simply if I don't even try Oxford there is no point for me to continue my highschool education...

Oxford and Imperial will reject you (they require A*s in maths and Further maths, and A's in all other subject)
UCL will reject you (at a minimum they require A*A* single and further, OR A*A in Mathematics and Further Mathematics, in any order, and a 2 in any STEP Paper or a Distinction in the Mathematics AEA)
Etc.
I don't mean to be patronising, but you have to play the cards you have been dealt - which (unless in the case of some exceptional admission test results and extenuating circumstances) is insufficient for any of the universities you have listed there.
Remember that they are the top institutions in the world with people frequently applying with 3, 4, 5 sets of full A* and high admission test results. Your application is unlikely to make it very far with any of the above listed universities, especially with a B in FM when you want to apply for Mathematics.
I highly recommend talking to your parents about this. You only get 5 applications, so using them on universities which you have a very low chance of getting into is unwise. Having one or two at most is fine, maybe KCL or Manchester as your most ambitious applications, but otherwise the rest should match up more closely with your academic profile.
Also remember, at the end of the day you will be spending 3-4 years of your life here. Even if you got into Oxford, Imperial or UCL, you need to consider whether the pacing will actually be right for you. Many talented 'ace' students shatter under these universities, so it is not something to take lightly.
Good luck whatever you chose.

my Final UCAS predictions are AAAB in Economics, Physics, Math and Further-math
parents are forcing me to look ambitious so I am really worries I can't get into any of my UCAS choices, they are currently Oxford, Imperial, UCL, KCL and manchester (I know Oxford Imperial are just delusional dreams, but is it possible for me to apply for UCL at all?)
Update: thanks for responding, a new short list in my head would be something like UCL, KCL, Southampton. Which unis are recommended by ps ranking? (that's the most important list Asian companies look at when I apply for a job)

my Final UCAS predictions are AAAB in Economics, Physics, Math and Further-math
parents are forcing me to look ambitious so I am really worries I can't get into any of my UCAS choices, they are currently Oxford, Imperial, UCL, KCL and manchester (I know Oxford Imperial are just delusional dreams, but is it possible for me to apply for UCL at all?)
Update: thanks for responding, a new short list in my head would be something like UCL, KCL, Southampton. Which unis are recommended by ps ranking? (that's the most important list Asian companies look at when I apply for a job)