Place Value Cups. Use the cups to understand place value practice counting forward and backward learn the names of large numbers decompose numbers to expanded form. I would either label the cups 'ones' 'tens' etc. or add a comma cup or decimal point cup
Give kids lots of opportunities to practice rounding numbers. Rounding numbers to the nearest ten with craft sticks. This is a quick & easy activity for learning stations/learning centers/small groups/cooperative learning.