The width of two Cu atoms is 2.6×10⁻¹⁰m=2.6×10⁻⁸cm.
We need to divide 10cm by this to find out how many times the copper wire needs to be divided:
10÷(2.6×10⁻⁸)=10x10⁸/2.6=3.8462×10⁸=384,620,000 approx.
(If we were to halve the length of copper wire to 5cm, then halve again to 2.5cm, and so on, we would only have to do this between 28 and 29 times to get to the width of two atoms!)