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

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

To describe how the numbers change in the given pattern, we need to observe the place value of the digits.

In the first set of shaded numbers: 501, 502, 503, 504, 505, 506, 507, 508, 509, the last digit (ones place) is changing sequentially from 1 to 9 while the first two digits (hundreds and tens places) remain constant at 5 and 0 respectively.

In the second set of shaded numbers: 510, 511, 512, 513, 514, 515, 516, 517, the tens place is changing sequentially from 1 to 7 while the hundreds and ones place remain constant at 5 and 0 respectively.

In the third set of shaded numbers: 518, 519, 520, 521, 523, 524, 525, the ones place changes sequentially from 8 to 5, the tens place changes from 1 to 2, and the hundreds place remains constant at 5.

In the fourth set of shaded numbers: 526, 527, 528, 529, 530, 531, 532, 533, the ones place changes sequentially from 6 to 3, the tens place changes from 2 to 3, and the hundreds place remains constant at 5.

In the fifth set of shaded numbers: 534, 535, 536, 537, 538, 539, 540, 541, the ones place changes sequentially from 4 to 1, the tens place changes from 3 to 4, and the hundreds place remains constant at 5.

In the final set of shaded numbers: 542, 543, 544, 545, 546, 547, 548, 549, 550, the ones place changes sequentially from 2 to 0, the tens place changes from 4 to 5, and the hundreds place remains constant at 5.

Therefore, from the given pattern, we can observe that the numbers change by sequentially incrementing or decrementing the ones and tens places, while the hundreds place remains constant at 5.