Silly me!

Argh~
How silly am I?
Dont even know how to calculate with calculator..
How can I press wrongly and get wrong for 3 questions??
My equations n substitutions are all correct d..How come??
I can never score in exams..
Always being in the middle one..lower than average I suppose..
Grr~Geram with myself..
Why I am so careless..so silly..so stupid..!!
Should jz go knock my head on the lamp post..*Long tiang*..
I'm so hopeless~