Binary is coding in 1's and 0's, 1 meaning yes, and 0 meaning no. For example, if you wanted a box to be filled in, you would code it to 1. If you wanted it to be empty, it would be 0, so basically, if you want something to exist or for something to happen, you would code it to 1 for yes, and if you don't want it to exist or don't want something to happen, you would code it to 0 for no, though there are points in exams where 01 is set to yes, and 00 is set to no, but in real coding this does not take place. This is only because a computer can only read in 0's and 1's.
Each finger on the hand can be represented by a different number in binary. By going through each finger, the number doubles. The image below shows that.
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