To hide (or show) widgets in particular posts, static pages, homepage or archive pages, you can use conditional tags.

1. First of all, go to Blogger's Dashboard >> Design >> Page Elements and give a name for the HTML/Javascript gadgets you have already added. Doing this it will be easy for you to identify the widgets in your blogger template. Give it a unique title so that it does not match with any of the titles of other widgets added.
2. Then go to Dashboard >> Design >> Edit HTML and check the "Expand Widget Templates" box.
3. Find your widget in the HTML by using Ctrl+F and entering the widget's name in the search box. Let's say i have given the title for my widget as "Recent Posts". After searching you will find the below snippets:

  

This code represents the widget/gadget that you have added in the Page Elements location. All you have to do is to add the following conditional tags marked with red just below and above to hide the widget from specific pages or posts in Blogger. Let's see some examples:
To show the widget only in Homepage:

To show Blogger widget only in post pages

To show the widget in a specific page

Note: Replace URL of the page with the address of the page in which you want the widget to appear
To hide a widget only in a particular page

To show widgets only in static pages

To hide widgets in Static Pages

To show widgets only in Archive Pages

After you have added the conditional tags, Save Template and view your blog.