Binary 21 is a fun way to practice your binary number counting skills. Touch and drag to connect the numbers to match the target number.
If you get stuck you can shuffle the entire board, or flip a bit from 0 to 1 (or 1 to 0). But you only get one shuffle and one swap every time you get to a multiple of 21.
Heres a hint to get your started if youre not familiar with binary.
Decimal = Binary
0 = 0
1 = 1
2 = 10
3 = 11
4 = 100
5= 101
6 = 110
7 = 111
8 =1000