Consumer Math

COUNTING MONEY & PROVIDING CORRECT CHANGE

No matter where you are, it is important to understand the currency of money you are using.

Counting money reviews the skills acquired studying the addition and subtraction of Decimals 

Good Tip:  Money always uses two decimal places.  (ex: $4.50  ~ even though the calculator may say 4.5) 

                          Remember to round to the nearest hundredths (ex: $3.25 ~ even though the calculator may say 3.2487432)

UNIT PRICE COMPARISON

When finding and comparing unit prices we usually see unit prices written as follows:   $ _______ . ___ ___  /  item.

        Example: $ 0.50 / envelope                                                                                        (dollars)       (cents)

To find a cost comparison between two prices, first find the unit price by dividing the amount by the number of items.

        Example:  3 bananas for $1                    or        12 bananas for $4

                           1 ÷ 3  =  $0.33 / banana                    4 ÷ 12 = $0.25 per banana

Once you have both unit prices, calculate your savings by subtracting the better unit price from the larger unit price.

        Example:  $0.33 - $0.25 = $0.08 savings

The difference can be quite small, even to the hundredths of a cent.

        Example:  a baker's dozen for $1     or     one dozen for $0.99

                          1 ÷ 13 = 0.0769 each                0.99 ÷ 12 = 0.0825 each

                                                    0.0825 - 0.0769 = 0.0056

                                  or     56 hundredths of a cent in savings

A clear understanding of unit price comparison is a benefit at the grocery store to find the best value for your dollar.

TAX, TIPS, ESTIMATES

Tax, tips, and estimates review the skills acquired studying the use of Percentages

To calculate the percentage of something, multiply the price by the decimal notation of the desired percentage.

        Example:  20% of $50 is 0.2 x 50 = $10

For mental calculation use benchmarks such as 10%.  The answer can then be doubled to find 20% or cut in half to find 5%

        Example:  10% of $50 = $5.0 (one decimal jump to the left)  

                                                 or for a 15% tip on a $50 bill...   $5 + half of $5 ($2.50) = $7.50 tip

Quickly calculate the price of something with the tax included as follows...

       If the tax is 15% multiply the original price by 1.15

                                                  this will account for the tax  ( original price x 0.15  )

                                                      and for the original price  ( original price x 1  )

        this hint will save you the extra step of adding the tax to the original price

SALES, DISCOUNTS, INCREASES / DECREASES

To calculate decreases or an increase in an amount also uses skills acquired studying the use of Percentages

First find the percentage of increase/decrease and then add or subtract it to the original amount.

        Examples:  10% pay raise from $10/hr = $1 + $10 = $11/hr

                              Sale of 25% off $50 jeans = 0.25 x 50 = $12.50    then    $50.00   -   $12.50  =  $37.50 jeans

                                                                                                                            (original price)  (discount)      (sale price)

                                      also found by multiplying original price by 75%...    $50.00   x   0.75   =   $37.50 jeans

                                                                                                                            (original price)  (% paid)        (sale price)

MONEY MANAGEMENT