Trick for 11

 If you want to multiply with 11

Then there is an easy method to multiply it with 11 as

    35

*.  11

________

3(3+5)8=388

__________

Now check it

123

x11

1(1+2)(2+3)3

1353

Is your required answer

Carrying

If.    298*11

=2(2+9)(9+8)8

=3278 by giving carrying to next