#29

Heather is buying a T-Shirt for $8. Sales tax is 8 1/4 cents per dollar.

This means that the tax rate is 8.25 percent. To calculate JUST the tax amount, you multiple the cost of the item (the shirt
for $8) by the percent, 8.25, which is written as 0.0825.

Note:
100 % = 1
90 % = 0.9
80 % = 0.8
etc.
1 % = 0.01
1/4 % = 0.0025 (You do the fraction and add whatever you get to the tail-end of the whole percent)

So 8 + 1/4 = 8.25 (or 8 and 1/4 percent)
8.25 % = 0.0825

$8 * 0.0825 = $0.66 dollars, or 66 cents.

If you are including the cost of the item in the total amount spent, then you add 100 percent to the percent you are multiplying by,
meaning, for example, that 0.0825 percent becomes 1.0825.

$8 * 1.0825 = $8.66