What do 2+2-4+10-9+1=

2+2-4+10-9+1=2

Step by step:

2+2-4+10-9+1

=4-4+10-9+1

=0+10-9+1

=10-9+1

=1+1

=2

Hence proved.

the answer will be the last one

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

note: the best i know.