To round a number to the nearest hundred, you make it into the hundred that is closest. Take the number 246, for example, which is between 200 and 300. It is closer to 200. So 246 rounded to the nearest hundred is 200.
Plagiarism is presenting someone else's work or ideas as your own, with or without their consent, by incorporating it into your work without full acknowledgement. All published and unpublished material, whether in manuscript, printed or electronic form, is covered under this definition.