Lesson Plans
Lesson 6 - Gift Shop Galore!
Objectives
Students will operate real life math application problems that deal primarily with amount of increase or decrease % of increase or decrease sale price and discount price adding tax.
Materials
- Calculator (teacher discretion)
- Inventory list of items found in Battleship North Carolina Gift shop
- Pictures of items (optional)
Teacher Input
Day One:
Discuss with students the idea of something being one half off of the original price. Ask them if they know how much the item will be? How? Give several verbal examples:
Move into the idea of 25% off of a price > will it be more or less than the 50%?
Introduce the formula that the students should become familiar with:
Amount of change = Percent
Original price 100
Example
A shot glass is 15% off of $3.95. How much is the sale price?
? = 15% 1. Cross Multiply
$3.95 100 2. Divide by lonely #
1. 3.95 * 15 = 59.25
2. 59.25 / 100 = .5925 > dealing with money > 2 decimals
$ .59 is the amount that the shot glass is discounted. Now take this amount and subtract it from the original price. This gives you the sale price.
$ 3.95 - $ .59 = $ 3.36
Other examples
Lighthouses 20% off of $11.95
Wind Chimes 10% off of $14.49
1 Dozen Postcards 60% off of $5.99
Once students get the hang of finding the discount price, you should change the problem by giving them the new price and the old price, and have them find the percent of discount. They will still use the new formula, they just need to find the amount of change between the prices.
Amount of change
Find the amount of change by subtracting the Original price new price from the old price.
Example:
New price of $5.99
Old price of $6.75
Amount of change = 6.75 – 5.99 = .76
Use formula:
.76 = ? 1. Cross multiply
6.75 100 2. Divide by lonely number
1. .76 * 100 = 76
2. 76 / 6.75 = 11% (round to nearest whole number)
After several examples, the students should feel comfortable starting the independent practice.
Day Two
On the second day, the students will be introduced to figuring tax on the items that they worked with yesterday. They will use the same formula that they used yesterday except for one difference (ask them if they know what that difference will be) (looking for an answer of adding instead of subtracting)
Example: The final price for the shot glass is $3.36. If the tax is 6%, use the formula to figure out the final price plus tax.
Amount of change = 6% 1. Cross Multiply
3.36 100 2. Divide by lonely number
1. 3.36 * 6 = 20.16
2. 20.16 / 100 = .20 (money and 2 decimal places) Add this amount
to the original price of 3.36 to find the price plus tax = $ 3.56
| Description of Item | Old Price | New Price | Percent of discount |
| Sitting Frog Thermos | $5.50 | 10% | |
| "I Love You Mom/Dad" Mug | $6.25 | $5.49 | |
| Dolphin Lamp | $44.95 | 30% | |
| Dinghy Bookshelf | $24.95 | $21.95 | |
| Cape Hatteras Lighthouse | $34.00 | 25% | |
| USS NC Sailboat Model | $69.95 | 15% | |
| Sailor Holding Beer Jewelry Box | $6.00 | $4.00 | |
| Battleship NC Suncather | $8.95 | 20% | |
| Battleship NC Fleece Pullover | $33.95 | 10% | |
| Battleship NC Colored Hats | $6.99 | $4.99 | |
| Battleship NC Magnets | $2.00 each | 15% on a purchase of 3 or more |
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