Twitter now has an answer to your math woes too. If you feel you are weak at calculating simple math in your mind (and that's why the name, Mental Math) then you are in luck. Ajaxorized has launched this cool web app called TwitBrain which puts in easy math calculation questions to you and you just need to reply to them, the faster you reply the more no. of points you collect and as the twitbrain website says, you eventually earn respect! And all this happens using twitter.
All you need to do is to follow TwitBrain using your twitter account. When a new question is posted, you just need to send TwitBrain a direct reply by sending this tweet: @TwitBrain youranswer to your profile. And in moments you will receive a tweet notifying you about the correctness of your answer. This is really good as you make productive use of your time as well as get good at mental math. Check the screenshot above.