Question

How do you simplify `5.2-2.09`?

Answer 1

I got `3.11`

Explanation:

I would write it as:

`520/100-209/100=(520-209)/100=311/100=`

dividing by `100` we get (moving the point from right to left):

`311/100=3.11`

Answer 2

`3.11`

Explanation:

Consider the 0.2 from 5.2

But this is the same as `2/10` and can be written as:

`0.2=1/10+[1/10color(green)(xx1)]`

`0.2=1/10+[1/10color(green)(xx10/10)]`

`0.2=(color(magenta)(1))/10+[(color(magenta)(10))/100]`

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How is this translated into something we can use? Do this:

`5.20`
`ul(2.09)larr" subtract"`

`5. cancel(2)^(color(magenta)(1))cancel(0)^(color(magenta)(10))`
`ul(2. color(white)(.)0color(white)(.)9)larr" subtract"`
`3. color(white)(.)1color(white)(.)1`