Calculating Change

Sometimes when making purchases, it could be difficult to determine change due mentally. Here's a method that is frequently used by shopkeepers/ hawkers, it uses mental addition instead of mental subtraction that most perople find difficult. It helps if there is a pool of money to make out the change immediately.Say $50 note is used to pay for a $6.35 item, what is the change due? First, put down 5 cents to make 6.40, then put down 60 cents to make 7.00, then put down $3 to make $10, lastly put down $40 to make $50. The required change is now on the table.