Okay I will try to explain in this chat. we know till twelfth nibble but not 13.25 (which is 53/4=13.25). so first convert the thirteenth and fourteenth nibble to binary (since it lies somewhere this range). i.e. 01010110 (8 bits of 2 nibbles) that means each bit is 0.25. now when you multiply 0.25 X 5=1.25. (it is fifth-bit position) Since you already know 12th, now when we add12+1.25=13.25. which is why it lies there. But I think you don't have to worry about this. since you know it lies somewhere after the 13th so just put zeros after.
@@networkingwithh4716 you wrote the last prefix as 2001:1234:abcd:5000:0:0:0:0/53 Where do those zeros come from? Because every other time you changed the host portion to zeros you used ::
So once you find the 53rd bit in the block, since it is not hexadecimal and its already in decimal format, you just leave the 5 and turn the rest to 0?
First 3 octets make 48. So 5 more to come to 53. So go from left to right in Binary "0101 0110 0111 1000" for 5 places and you end up with "0101 0" which will be 5 in value I think. I could be wrong!
