AB is a two-digit number. BA is the two-digit number with the 2 digits of AB interchanging position.
(i) Observe what happens when you perform AB - BA. Try different combinations of AB and BA.
(ii) Explain/proof (using Algebra or otherwise) why the results in (i) always turn out to be multiples of 9?
(i) Observe what happens when you perform AB - BA. Try different combinations of AB and BA.
(ii) Explain/proof (using Algebra or otherwise) why the results in (i) always turn out to be multiples of 9?
