Remove Number Indicator – Know Abacus Review

This is a great App! My only suggestion is to allow the function to turn on and off the number indicator. By not seeing the number will challenge the user to be confident in his or her answer. The user would not be able to advance to the next question unless they get it right. If the user struggles then they should be able to turn on the function to see the number indicator to help them find their mistake. Make sense?
Review by OohOrganic on Know Abacus.