Can you solve this tricky riddle in less than 60 seconds?

[ahlam1399]

http://img-s-msn-com.akamaized.net/tenant/amp/entityid/BBnh3p2.img?h=100&w=100&m=6&q=60&o=f&l=fFor some people, math comes naturally.

أكثر... (http://www.msn.com/en-ca/lifestyle/whats-hot/can-you-solve-this-tricky-numbers-riddle-in-less-than-60-seconds/ar-BBHV71p?srcref=rss)