Google-sheets – How to embed a Google Spreadsheet inside a post in the blog

From Google Docs Help:

Publishing

Once you're done creating and editing your spreadsheet, you can publish it to a webpage. >Just click the Share drop-down menu on the top right and choose Publish as a webpage. Then, click Publish now.

Then, everyone you choose can access your spreadsheet by entering the URL you send them into their browser's address bar.

Even after you publish a spreadsheet, it won't appear in any search index.

Embedding

After you publish your spreadsheet, you can share it with the world by embedding it (or parts of it) in a website or blog.

Publish your spreadsheet following the steps listed above and a unique URL is generated. Use this URL to embed the spreadsheet on your website or blog. You can also insert a spreadsheet in Google Sites. Just click Edit page > Insert > Spreadsheet from within your site. You'll need to enter the URL of your spreadsheet to embed it.