Twelve is a cool puzzle game that will surely work as a mind teaser game for kids. The game starts with a tutorial to learn.
Each time you add 2 number of same value it gets 1 digi bigger. For example, merger two pieces of number 2 will give you 3 and not 4. In the same way, merging 2 pieces of number 6 will give you number 7 and not number 12.