I’ll skip all the technicalities (including jargon) and use concrete exemplification in concordance with basic terminology
Say you have (1/5)
To find the inverse, flip the roles of the denominator and numerator – substitute one for the other: i.e. (5/1 => 5)
Now, apply the opposite sign.
For 5, from a positive, you would have a negative. likewise, from a negative, you would apply a positive.
(8/7) would be (- 7/8) etc.
In extension, if you have decimals, multiply the decimal components (i.e. .3) by a factor of 10 to make it whole etc.
That’s all to it