Question

if
0000 = 0
0001 = 1
0010 = 2
0011 = 3
0100 = 4
0101 = 5
0110 = 6 and
0111 = 7
What number is equal to 12?

Answer 1

do you know the binary system?

Answer 2

This means 0000 is 0, 0001 is 1, 0010 is 2 and so on to 1001 being 9, but then from 1010 to 1111 of binary the hexadecimal uses letters from A to F and then when it reaches the value of 16 it becomes 10 because the two groups of four binary numbers are 0001 0000
I think

Answer 3

1000 is 8
0100 is 4
basically from the ones digit it's one... the tens is 2^1.. the hundreds is 2^3... etc.

looking at the list from the question...
0 is like an off switch, 1 is on
0000 is 0 because nothing's turned on
0001 is 1 because 2^0, the one's place, is 1
0010 is 2 because 2^1 is 2...

1 1 1 1
8 4 2 1
so basically if all four digits were ones.. turned on.. it would be 8 plus 4 plus 2 plus 1

looking back at the question
12...
you want the digits that add together to equal 12 to be as a power of two, because that's what the binary system gives
and 12 is 4 plus 8
and since you want to add those together.. you basically need a 1 at the point where it's 8 and 4... which is `1100`
since 1000 is 8 and 0100 is 4