add todo comment in checkAnswer method
Merge remote-tracking branch 'upstream/practice-mode' into practice-mode
Merge remote-tracking branch 'upstream/practice-mode' into practice-mode
Merge branch 'master' into practice-mode
fix level 12, starts at level 1
Merge pull request #13 from hitraj47/practice-mode

Practice mode
update
Merge remote-tracking branch 'origin/master'
levels up to 16 have been created and are good to go