Question

How do you convert 1/5 into a percent and decimal?

Answer 1

`1/5->0.2`

`1/5->20/100->20%`

Explanation:

`color(blue)("Convert "1/5" into decimal")`

`color(brown)("Shortcut method"`

divide 5 into 1

But 1 is less than 5

Known: multiply anything by 1 and you do not change its value.

Suppose we had `1/5 xx 1` but wrote it as `1/5xx10/10`

This is the same as `(1xx10)/5xx1/10" " ->" " 10/5xx1/10`

Which is the same as `2xx1/10" " ->" " 2/10 =0.2`

'........................................

`color(brown)("Another approach")`

As the first decimal place is measuring/counting in tenths and you recognise that `2xx5=10` then do this:

Multiply by 1 but in the form of `1=2/2` giving

`1/5xx2/2" "=" "(1xx2)/(5xx2)" "=" "2/10 ->color(magenta)( 0.2)`
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(blue)("Convert "1/5" into percent")`

`color(brown)("Shortcut method")`

`1-:5 xx 100" " =" "color(magenta)( 0.2)xx100" " =" " 20%`

This is the same as `20/100`