I teach my students with and without disabilities to use rounding hills. This doesn't work for every teacher and student, but I've had great success with it. These cards can be put on a ring as a center, printed as worksheets, used for Scoot... Plenty of ways to use it. An answer sheet is included. The activity involves some scaffolding- the last eight of the 20 cards require students to identify which tens the number being rounding goes between.