I have created a fun activity to introduce rounding to the nearest 10 (which is also the basis for rounding in general). Some students hold "Island Cards" (numbered in 10's from 0 - 100) while others are given numbers anywhere between 1 and 99. (These students are "swimmers"). When the teacher yells "Shark", the students must "swim" to the nearest island to escape being attacked by the shark. This activity meets the learning-style needs of visual, auditory, and tactile-kinesthetic learners. This file is 15 pages and includes instructions, "island" cards, a practice sheet, and a quiz.