for loop id with CKEditor [duplicate]

I have many same blocks of Javascript code with only difference is the id.

if(numEduIndex == 1){
    var editorEduDes = CKEDITOR.instances.edu_description_1;
    editorEduDes.on('paste', function (evt) {copyPasteCkeditor(evt)});
}
if(numEduIndex == 2){
    var editorEduDes = CKEDITOR.instances.edu_description_2;
    editorEduDes.on('paste', function (evt) {copyPasteCkeditor(evt)});
}
if(numEduIndex == 3){
    var editorEduDes = CKEDITOR.instances.edu_description_3;
    editorEduDes.on('paste', function (evt) {copyPasteCkeditor(evt)});
}

I want to use for loop to clean code, like this:

for (let i = 1; i <= 31; i++) {
   if(numEduIndex == i){
      var editorEduDes = CKEDITOR.instances.edu_description_ + i;
      editorEduDes.on('paste', function (evt) {copyPasteCkeditor(evt)});
   }
}

The problem I have is I can not concat i to the id edu_description.
Is there anyway I can do this with for loop?

Thank you all!