This post shows an approach to teach rounding to the nearest 10 and is presented on a handout. Multiple strategies are used. This includes scaffolding, chunking with supports incrementally faded, and a visual.
Overview
A visual of the hand releasing the balloon draws upon prior knowledge and provides a mnemonic for when to round up. The scaffolding provides support to focus on fewer parts of the problem. The supports are faded to incrementally increase task demand placed on the student.

Handout
The first page has maximum scaffolding with the student focusing only on which tens to round to. In turn, an a different element is the focus (e.g., writing the 0s then rounding) and then the scaffolding is increasingly faded.

Links to Handout
Here is a link to a WORD document so you can change numbers AND add digits in the hundreds. Here it is in PDF for easier access.