Your situation is due to the Auto add widget due to which when ever you install an app it wall automatically add an widget on your home screen thereby increasing the home screen count also.
I will first solve your home screen problem and below I will also give a screen shot where the problem can be solved for the future also.
The below steps is easy to follow and requires some patience to clean the clutter.
There are two ways to clean a home screen in any Android device.
Option 1 will help you clean your home screen through the apps available in the play store.
Download any launcher which suites your requirement like GO Launcher from the play store and clean the home screen as per your requirements from the settings.
If you don't want any hassle of any more apps then go for Option 2
Step1-Do a normal zoom out in home screen (or) From home screen page, press the Option button, then click Edit and it will display all the home screens and their content.
Step2-Either click on remove and remove all the home screens except for 1 or you will be getting a small minus (-) symbol right side corner of the home screen. Click on the minus and remove it.
Step3-If you have followed the above 2 steps correctly then you will be getting a single home screen from which you can easily delete the widgets(it solved your problem of deleting around 84 widgets and brings the count to only 12 with just a single home screen).
Step4-Under the Play store settings uncheck the auto add widget in order to ensure you do not face the problem in the future.