This Flipping number cards activity, is part of problem solving course that I teach to middle and high school children. The activity starts with all (70) cards facing down. And then the following steps are performed in order, starting from the left most (1st) card in the 1st row and proceeding to right, and then repeating the same in other rows, till we reach the last (70th) card, in the seventh row: 1. Flip over every card 2. Flip over every 2nd card 3. Flip over every 3rd card 4. Flip over every 4th card and so on.. You flip over a card by simply clicking on it. Can you predict which cards (if at all any), will remain face up, once the activity is completed? Of course, you can perform it to tell the answer, but can you predict before you perform the activity? In either case, if some cards are left face up, why do they remain face up and others face down? Write in your comments in the comments section. Good luck! #Puzzles #Mathematics #AlgorithmicThinking #Algorithms #ProblemSolving #MathsAndFun #MathsAndScratch