Mathematics, Measurement (includes Time), Operations (+, -, x, /, etc.), Problem Solving

Grade 4- 6

Objective

Students learn about decimal arithmetic and multiplication.

Directions

Facts to Know
You often hear commercials about savings at stores. Sometimes, the announcer will say in the same breath, "We're having our biggest sale of the year, and all items have been discounted by 30-50% off!"
Well, what's the difference between things being on sale and things being discounted?
Having a sale is the act of selling at lower prices than usual, as in "Dorothy's House of Dresses is having a sale on skirts and jackets."
A discount is used by manufacturers and merchants to mean taking off a certain percentage of the price given in a price list. This price is called the list price. The list price less the discount is known as the net price. The noun "discount" can be used as a verb, too--"We're discounting by 15% the list price on all new cars and trucks during our storewide 'Get into Spring' sale!"
You can ask, "What's the discount?" but you would never ask, "What's the sale?"
Often you have to figure out your own savings during a sale, and this is when an understanding of decimals and percents comes in handy.
Sample
A local carnival is offering a single, one-day pass to all rides for $12.50 or a special two-day pass for $20.00. You do some quick decimal arithmetic.
Cost of 2 one-day passes
$12.50 x $2.82 = $25.00
2 one-day passes - special two-day pass
$25.00 - $20.00 = $5.00
So your savings on a two-day pass is $5.00.
But what percent off is that?
Cross Multiply
$5.00/$25.00 = x/100
25x = 500
x = 20 or 20% off

Resources

• Calculate Discounts and Sales activity sheets
• pencils