When you fold a piece of paper, it doubles in width. If you double it 51 times: 251 ≈ 2.25 x 1015.
A sheet of paper is approximately 0.1 mm.
0.1 mm x 2.25 x 1015
= 2.25 x 1014 mm (multiply by 0.1)
= 2.25 x 1013 cm (divide by 10)
= 2.25 x 1011 m (divide by 100)
= 2.25 x 108 km (divide by 1000)
= 225, 000, 000 km
The distance from the earth to the sum is approximately 149, 600, 000 km