Page
Lesson 5 β Activity 4: Estimating and Calculating Percents
Completion requirements
Lesson 5 β Activity 4: Estimating and Calculating Percents
Getting Ready
In the previous activity, you practised writing percents as decimals. That work will help you in this next activity.
Canada has a 5% General Sales/Service Tax (GST) on most items. Some provinces have an additional Provincial Sales Tax (PST) that is added to the cost of a purchase.
Here
are some examples of products with the GST added to the cost of the
item. First the 5% was changed to a decimal number to calculate: 5% to
0.05.
Item and Price |
GST Added |
Total Cost |
---|---|---|
Blender - $89.00 |
$89.00 x 0.05 = $4.45 |
$89.00 + $4.45 = $93.45 |
A chocolate bar - $0.69 |
$.69 x 0.05 = $0.03 |
$0.69 + $0.03 = $0.72 |
Ski jacket - $159.00 |
$159.00 x 0.05 = $7.95 |
$159.00 + $7.95 = $166.95 |
As mentioned previously, some provinces have an additional Provincial Sales Tax (PST) which is also added to the cost of a purchase.
British Columbia has a 7% PST, as well as the 5% GST. That's an additional 12% (0.12) to the cost of an item.
If you were in B.C., your cost for a ski jacket would be:
A simpler way to figure out the GST and the PST would be to estimate the cost of the GST and PST by adding 10% of the cost.
Remember that 10% in decimal form is 0.10.
Looking at the ski jacket once again:The cost is $159.00 x 10% (0.10) = 15.90 + 159.00 = $174.90. You could estimate that the ski jacket would cost a little more than this. (It actually costs $178.08)Let's try another one:You are looking to buy ski pants as well while in B.C. They are on sale for $97.00. Let's estimate the cost with GST and PST added.Again, let's use 10%:$97.00 x 0.10 = $9.70 + $97.00 = $106.70.You could estimate that the ski pants will cost a little more than this in total.If
you need to know the exact amount, you can calculate the cost including
GST and PST by multiplying by 1.12 because 100% plus 12% is the same as
1.12. |
Try This:
Calculate the GST (5% or 0.05) and the total costs on these items:
- T-shirt, which sells for $15.95
- sunglasses, which sell for $49.98
- wallet, which sells for $11.88
T-shirt: $15.95 x 0.05 = 0.80 + $15.95 = $16.75
sunglasses: $49.98 x 0.05 = $2.50 + $49.98 = $52.48
wallet: $11.88 x 0.05 = 0.59 + $11.88 = $12.47
Remember, you can also use the % key on your calculator to calculate a percent. Type the number x 5% to find out the amount of GST, or type the number + 5% to find out the total including GST.
Money and Decimals
Here's a review for you:
- The decimal number 0.05 is the same as 5 pennies out of 100 and can be represented as 5%.
- The decimal number 0.69 is the same as 69 pennies out of 100 and can be represented as 69%.
- The decimal number 1.45 is the same as 145 pennies and can be represented as 145%.
- The decimal number 0.05 is the same as 5 pennies out of 100 and can be represented as 5%.
- The decimal number 0.69 is the same as 69 pennies out of 100 and can be represented as 69%.
- The decimal number 1.45 is the same as 145 pennies and can be represented as 145%.
Sometimes you may see this kind of ad when looking for music to download:
Hurry!
Limited Time Offer!
This certificate earns you 20% off the cost of music of your choice if you download today!
The music Les wants costs $16.99. He is planning to use his 20% off certificate. He has exactly $13.75.
With the 20% discount, will Les have enough money to buy the music?
Letβs find out:
Step 1: Write down the original price of the item: $16.99.Les has enough to get the music he wants. |