Kilo to normal people means 10^3 or 1000
Computer people are not normal--they evolved with two toes on each foot, and can only count in base two. But they WANT to be normal, so they tried to get as close as possible. The figured out that 2^9.9658 was VERY close, but then they discovered that they could not make the CPU do non-integer exponentiation. Sadly, they had to settle for 2^10 = 1024.
Life is full of compromises........