Emily has $1.24. Joey has $5.36. Maria has $2.42. Do they have enough money to purchase a CD for $9.00?

To answer this question, we must first find the total amount of money the three people have all together. Then we can compare that total to the cost of the CD.
`1.24 + 5.36 + 2.42 = 9.02`
`9.02 >9.00`
Since $9.02 is more than $9.00, the three people together do have enough money to purchase a $9.00 CD, assuming there will be no sales tax added to the price.

It is much easier sometimes to write the numbers in column form. That is:

`color(white)(2)1. color(white)(2)2color(white)(2)4`
`color(white)(2)5. color(white)(2)3color(white)(2) 6`
`color(white)(2)ul(2. color(white)(2)4color(white)(2)2) larr" add up the columns"`
`color(white)(2)ul(color(white)(2" "))`

`color(blue)("'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~")`
`color(blue)("Step 1: add up the rightmost column")`

`4+6+2=12 -> color(red)(1)color(blue)(2)`

The `color(blue)(2)` goes in the right most column and the `color(magenta)(1)` is included in the adding up of the next left column

`color(green)(color(white)(2)1. color(white)(2)2color(white)(2)4)`
`color(green)(color(white)(2)5. color(white)(2)3color(white)(2) 6)`
`color(green)(color(white)(2)ul(2. color(white)(2)4color(white)(2)2)) larr" add up the columns"`
`color(white)(2)ul(color(white)(2" "color(blue)(2)))`
`" "color(red)(1)`

`color(blue)("'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~")`
`color(blue)("Step 2: add up the next left column")`

`2+3+4+color(red)(1)" " larr" don't forget the carried 1"`

`2+3+4+1=10->color(red)(1)color(blue)(0)`

`color(green)(color(white)(2)1. color(white)(2)2color(white)(2)4)`
`color(green)(color(white)(2)5. color(white)(2)3color(white)(2) 6)`
`color(green)(color(white)(2)ul(2. color(white)(2)4color(white)(2)2)) larr" add up the columns"`
`color(white)(2)ul(" "color(blue)(0)color(white)(.)color(green)(2))`
`color(white)(.)color(red)(1)color(white)(....)color(green)(1)`

`color(blue)("'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~")`
`color(blue)("Step 3: add up the last column")`

`1+5+2color(red)(+1)" " larr" don't forget the carried 1"`

`1+5+2+1= color(blue)(9)`

`color(green)(color(white)(2)1. color(white)(2)2color(white)(2)4)`
`color(green)(color(white)(2)5. color(white)(2)3color(white)(2) 6)`
`color(green)(color(white)(2)ul(2. color(white)(2)4color(white)(2)2)) larr" add up the columns"`
`ul(color(white)(.)color(blue)(9.)color(white)(.)color(green)(0)color(white)(.)color(green)(2)) larr" don't forget the decimal point"`
`color(white)(.)color(red)(1)color(white)(...)color(green)(1)`