textchanged event of dynamically created textbox is not working properly

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C#

C#4.0

i m developing window application using c#.i m created few textbox dynamically. and add textchanged event handler of those dynamically created textbox.

but eventhandler not working properly.
for ex

when i m pressing any int number to that textbox.
i want ten times of that input no.
like if i input 90,55.
answer should be 900,550 respectively.

but the same is not happening

if i inputing 9 i get 90, but after inputing 0 after 9 ,ans is not changed.i m getting same 90.

what should be the prblm?
can anyone help me.
THANKS IN ADVANCE!