If they gave you $20 to buy a $5 book, they will leave with $5 worth of book plus $15 worth of change, for a total value of $20.
For example, if you were given $10 for a $6 product, you would either: Count the one dollar bills and then give the total: “One, two, three, and four makes ten. ” Or add up as you go: “Seven, eight, nine, and ten. ”
In our initial example, you are starting with $7. 59 (the price of the sandwich), so you would hand back: 1 penny (“that’s $7. 60”) 1 nickel (“7. 65”) 1 dime (“7. 75”) 1 quarter (“8. 00”) While this is the most efficient combination of coins, it doesn’t really matter how you add up to $8. 00, so long as you get there.
You have added up to $8. 00 and need to continue to $20. 00, so now you would hand back: 2 one dollar bills (“9, 10”) 1 ten dollar bill (“and 10 more makes 20”)
For example, if the customer bought a $42 hat and gave you $47, you would count: 1 five dollar bill (“You gave me 42, plus 5 makes 47. ”)
Start with the amount paid. Subtract from it to get a simpler number. In this case, 23. 03 – . 03 = $23. 00. Now subtract the same amount from the price: 12. 78 – . 03 = $12. 75. It’s clear now that you’ll need to first give back a quarter. 1 quarter takes you from $12. 78 to $13. 03. (“that’s $13. 03”) 1 ten dollar bill (“plus 10 equals 23. 03”)
Add the amount paid by counting up as you put the money down: 20, 40, 60, 80, 100, 120 and six cents. Tell the customer the amount paid: “$120. 06”. The customer gave you a bizarre amount of change, so this might be a good time to do a bit of subtraction. 120. 06 - . 06 = $120. 00, and 112. 31 - . 06 = $112. 25. Better. You need 3 quarters. Now start adding up from $112. 31 to $120. 06. 3 quarters (“takes us to 113. 06”) - We know this works from our earlier subtraction exercise. 2 one dollar bills (“114, 115”) 1 five dollar bill (“and 5 is 120. 06”) Check your work: You gave . 25 + . 25 + . 25 + 1 + 1 + 5 = $7. 75. $7. 75 + $112. 31 = $120. 06 – the amount the customer paid.
