What is the difference of 9.4-7.9?

2 Answers
Jul 10, 2016

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.

Jul 12, 2016

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