box-sizing and box-sizing:border-box

[Deane]

I am running a test for my students, and I asked them to calculate the width of a box using the standard box model and box-model:border-box. I've gone over this in class, but not enough. They were Googling it and they can't understand how to do it from reading the instructions on W3 Schools. Reading it myself, I can understand why. (Some of it is a semantic question about whether the margin is part of the size of the box.) Is it possible to write your definition more clearly? Could I offer some help?

[Ingolme]

The website owners are not frequently on the forums, but if you think there is something that should be fixed, there's a "report error" button on every page on the site. Clicking on it will let you provide feedback about the content on the page. Here's the page describing the box model [https://www.w3schools.com/css/css_boxmodel.asp], you can use the "report error" feature there.