Magnetic number fishing, they add what they catch! As well as addition, develops hand/eye coordination, fine motor--I love this for magnetic letter fishing too! When they catch a letter, they say its name and sound.
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