Are you rather rational, or emotional ?
In either type you can have fun with this puzzle, SUMAHOJIN !
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If you are rather rational, have fun with magic-square puzzle. That is, by dragging pieces of number , to match the sum of any ACROSS, DOWN, and DIAGONAL!
If you are rather emotional, have fun with flush cards.
That is, by memorizing the arrangement of 16 cards for several seconds to find later a couple of numbers swapped each other.
For businessmen before engagement who want to
warm up the their brains, for students before exams.
For children.
Teachers and instructors tend to increasingly pay attention to this app to better pupils skill in arithmetics and math!