Look at the pattern of shaded numbers. use place value to describe how the number change.

Question

501,502,503,504,505,506,507,508,509 is shaded,510,511,512,513,514,515,516,517 is shaded, 518,519,520,521,523,524,525 is shaded,526,527,528,529,530,531,532,533 is shaded,534,535,536,537,538,539,540,541 is shaded,542,543,544,545,546,547,548,549,550