Question

how many bites have their second, third and fourth digit equal to 0

Answer 1

How many bytes have their second, third, and fourth digit equal to 0.

If we refer to 8-bits, we would have a value from 00000000 to 11111111, there would be a total of 256 values.

$2^8=256$

Considering that we only need it to have its second, third and fourth digit equal to 0, we can add the values from 2^0 up until 2^4

$2^0+2^1+2^2+2^3+2^4=1+2+4+8+16=31$

That would be equal to 31 bytes.