Decimal Operations

Study Guide Review

Steps

1. Line up the decimals

2. Add zeros to any blank spaces

3. Add or subtract starting at the right

4. Bring down the decimal point

Steps

1. Stack the numbers vertically

2. Multiply the numbers together (Forget about the decimals for now!)

3. Count the decimal places in each number

4. Scoop the decimal point in the answer

Steps

1. Change the divisor to a whole number (Hint: Scoop the decimal point to the right)

2. Scoop the decimal point the same number of places in the dividend

3. Bring up the decimal point

4. Now divide!

The Best Deal

Big image

How do I find it?

1. Change any fractions to percents. (Hint: Percents are always out of 100)


2. Compare all of the percents. Which percent is the highest?

(Hint: The highest percent will give you the greatest discount or the best deal!)


3. Compare the percent and the dollar amount by converting the dollar amount to a percent ($ Off divided by Total $) OR by converting the percent to a dollar amount (Change the percent to a decimal and multiply the total amount of $ by the decimal).

Calculating Sales Tax

Steps

1. Change the percent to a decimal

(Hint: Remember to scoop the decimal point two places to the left.)


2. Multiply the original price by the decimal to find the tax

(Hint: Remember to round the decimal to the nearest cent!)


3. Add the tax to the original price for your final cost

Calculating Sales Tax

Calculating Tip

Steps

1. Change the percent to a decimal

(Hint: Remember to scoop the decimal point two places to the left.)


2. Multiply the original price by the decimal to find the tax

(Hint: Remember to round the decimal to the nearest cent!)


3. Add the tip to the original price for your final bill

Finding Math in the Real World: Calculating Tip

Calculating Discounts

Steps

1. Change the percent to a decimal

(Hint: Remember to scoop the decimal point two places to the left.)


2. Multiply the original price by the decimal to find the tax

(Hint: Remember to round the decimal to the nearest cent!)


3. Subtract the discount from the original price

Percentage Discounts

Rates & Ratios

A ratio is a relationship between two numbers by division.


A unit rate is a ratio with the number one in the denominator.

Proportions

Proportions are two ratios that are equal to one another.