We loved collecting shells and small smooth pebbles from the beach or when out for walks.

Write numbers onto the smooth pebbles.  They are so tactile and lovely to order. 

I used a silver pen to write the numbers.  They always write well on smooth pebbles.

 

You could put coloured dots onto the pebbles and use them to make patterns.

 

See 'Ordering Numbers' in 'Maths Play'.   p.132 - p.137