Respuesta :
The leading zeroes are not significant, just place holders.
0.0008515 = 0.0009 (1 sf) or 0.00085 (2 sf) or 0.000852 (3 sf) or 0.0008515 (4 sf)
0.0008515 = 0.0009 (1 sf) or 0.00085 (2 sf) or 0.000852 (3 sf) or 0.0008515 (4 sf)