I break down the process of rounding off into 4 parts. The process revolves around using a number line.
Part 1 is to help students learn to fill in the steps of a number line.
Part 2 is to help students learn where to position a given number in a number line.
Part 3 is to help students decide which of 2 numbers a given number is closer to.
Part 4 gives students practice in rounding off using a number line.
Part 5 is the advanced section.
You can use parts 1, 2 and 3 for younger students so they have more time to really understand the concept.
The pages of the pdf is half letter size. This allows you to print the pages onto small index cards so you don't have to cut to make task cards.
You can also use the multiple pages function of your printer to make customized worksheets for your students. Just be sure to change the paper size to your paper before printing.
You can try printing out the preview pages to see what I mean.