Drupal 7 on the front page will display, by default 10 posts. Here you can find how to change that setting, by editing the number of posts value.
This is one of settings you can not find easily, due to lot of Drupal's configuration parameters.
You can do it in next few steps:
- In administrators' top menu choose Configuration
- On next page click on link Site information
- In the Front page section, change Number of posts on front page value, to one you need
- Save configuration and that's all
- Refresh home page of your website, and you'll see the difference.