Question

What is `3.68+8.21`?

Answer 1

11.89

Explanation:

You can see what is happening if you arrange the numbers this way:

`3.68`
`ul(8.21)" "larr" Add up 1 column at a time right to left"`
'................................................
`8+1=9` so we have:

`3.68`
`ul(8.21)`
`" "9`
,.............................................................

`6+2=8` so we have:

`color(white)(....)3.68`
`color(white)(....)ul(8.21)`
`color(white)(.......)89`

'...................................................
Now we add the decimal point

`color(white)(....)3.68`
`color(white)(....)ul(8.21)`
`color(white)(......).89`

,..................................................................
`3+8=11` so we have:

`color(white)(....)3.68`
`color(white)(....)ul(8.21)`
`color(white)(..)11.89`