
A Fuzzy Calculator
How fuzzy arithmetic works
You can use fuzzy numbers for fuzzy arithmetic. This can be done by the application of Zadeh's extension principle.
With the use of this principle I made a simple fuzzy calculator. There are two fuzzy numbers on it: A and B.
In the default mode A is a "fuzzy 2" with boundaries 1 and 3 and B is a "fuzzy 4" with boundaries 3 and 5. Below each subnumber of a fuzzy number its grade of membership is shown.
The result of an arithmetic operation is shown in Fuzzy C, which is an approximation of a new fuzzy number.
The main purpose of this fuzzy calculator is to show how the extension principle works.
Therefore I made the grades of membership of the lower and upper bounderies of fuzzy A and fuzzy B in the default mode not completely zero.
I let them approximate zero all slightly different from each other in order to make them traceable in the handling of the extension principle.
By clicking on "Cartesian Productspace" in the fuzzy calculator you can make this cartesian productspace visible and see the new subnumbers and the grade of membership assigned to each of them.
You can change the subnumbers of fuzzy A and fuzzy B in the fuzzy calculator to make new fuzzy numbers and new computations. Also you can change the grades of membership. Always keep in mind that these grades do belong to the closed interval [0, 1].
Below, there also is a link to some diagrams of arithmetical operations on the default fuzzy numbers of the fuzzy calculator. It should be stressed that the diagrams of the results (in blue) are approximations.

