When did we lose subtraction?

We all have calculators now (hard or soft). So hardly anybody learns arithmetic, right? Cash registers tell the clerk exactly how much change to give us. In the last thirty years we’ve forgotten the higher skills of arithmetic, right?
Well it’s not so simple. If you worked in retail before calculators, you were taught to give change without subtracting. You were only expected to know addition, and if you handled change correctly you might not even know how much change the customer got. Sounds strange?

Suppose I buy something for 47 cents and hand you a dollar. Opening the register, you pick up three pennies, counting “48, 49, 50.” Then you pick up two quarters, counting “75, 100. Here’s your change, sir.”