With the number 529, the 5 is the most significant digit, because it tells us that the number is 500 and something. The 2 is the next most significent digit. After that digit is 9, so we will round it and add 1 onto 2 ( 2 + 1 = 3 ). Finally, 529 to 2 significant figures is: 530 ( and the second significant digit (3) has the overline ).