Question

What is the difference of `9.4-7.9`?

Answer 1

1.5

Explanation:

`9.4 - 7.9` = 1.5

You can check this answer by adding 7.9 to 1.5 and you will end up with 9.4.

Answer 2

Solution method taken one step at a time with a lot of detail

`1.5`

Explanation:

`color(blue)("This is how the process should look and it is very quick:")`

`color(white)(..)cancel(9)^8 .cancel(4)^14`
`color(white)(..)ul(7color(white)(..).9)`
`color(white)(..)1color(white)(..).5`

`color(white)(..)`
`color(white)(..)`

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(blue)("This is the very detailed explanation")`

Write as:
`" "9.4`
`" "ul(7.9) larr" Subtract"`

Work from right to left
'~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(green)("Subtracting the right column")`

Notice that the right hand column the 4 is less than the 9.

For subtracting this part we have `color(red)(9+4/10)color(blue)( -9/10)`

This is the same as `color(red)(8+14/10)color(blue)(-9/10)`

So in our subtraction of the right column, instead of having:

`color(white)(.)9color(magenta)(.4)`
`ul(color(white)(..) color(magenta)(.9)) larr" Subtract"`

We have:
`color(white)(.)8color(magenta)( .cancel(4)^14)`
`ul(color(white)(....) color(magenta)(.9)) larr" Subtract"`
`color(white)(....)color(magenta)(.5)`
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(green)("Subtracting the left column")`

`color(white)(..)color(magenta)(8) .cancel(4)^14`
`ul(color(white)(..)color(magenta)(7) .9) larr" Subtract"`
`color(white)(...)color(magenta)(1).5`

`color(white)(..)`

9.4 - 7.9 = 1.5