Taxi Passenger: How much I owe you?
Taxi Driver: That will be £7 please.
Ten.
There you go, £3 change.
Thank you.
Taxi Passenger: Thank you very much.
Taxi Driver: I use subtraction, when I'm giving customers change, because it's important to get it right, and so the customer don't feel as if I'm ripping them off.
Male sitting at a desk, wearing glasses and red tie: I would do subtraction when somebody phones up; I'll take a note of what time they phoned up.
And then I would carry on working on their case, and when they finish, and make a note of what time that I finished working on the job.
Female with long black hair, wearing black top: Subtraction help me to reorder the stock.
I'm meant to have 30 bowls of these.
I have ten now.
That means I need to reorder 20 bowls more.