Write down any three-digit number, e. g. 287. Arrange the digits in order of size, once with the largest digit first and once with the smallest digit first, i. e. 872, 278. Now find the difference between these two numbers (take the smaller number from the larger number). 1.e. 872 -278 = 594. Repeat the process for your answer, ie 954 - 459 = 495 Repeating the process again, je 954 - 459 = 495. These rules give us a chain of numbers. In this example we have 287 - 594 495 495. Form a similar chain for a three-figure number of your own choice. Try a few more. What do you notice ?