2 The following is called the '1089' algorithm. In steps 1 to 4 numbers are to be written with exactly three digits; for example 42 is written as 042. Step 1 Choose a 3-digit number, with no digit being repeated.
Step 2 Form a new number by reversing the order of the three digits.
Step 3 Subtract the smaller number from the larger and call the difference D. If the two numbers are the same then \(\mathrm { D } = 000\). Step 4 Form a new number by reversing the order of the three digits of D , and call it R .
Step 5 Find the sum of D and R .

1. Apply the algorithm, choosing 427 for your 3-digit number, and showing all of the steps.
2. Apply the algorithm to a 3-digit number of your choice, showing all of the steps.
3. Investigate what happens if digits may be repeated in the 3 -digit number in step 1 .