Hello, sir I have crossed the cut off jee advance paper but I didn't crosse the subject cut off(tatal-8 in mathematics paper).

Hello Sushil
No you can not take admission in IIT colleges.
As per the rules you have to qualify the jee advanced with a good and decent rank along with qualifying marks in each subject also.
Thats why the committee announced the each subject qualifying marks ( otherwise why it declared the cut off for each subject also.)
Hope you understand it .
Good luck