Rekenreks are another way for your child to "see" numbers up to 20. They are designed to help children see groups of 5 and 10 (benchmark numbers) quickly. They can then see how many more they need to get to their next 5 or 10.
Here is my large Rekenrek. I use it for whole group instruction. (It's amazing what you can do with pool noodles, pipe, and 90 degree connectors.)
This is representing 18. A child can quickly see 3 groups of 5 and 3 more,10 and 3 more, or even 10, 5, and 3 more.
Here is what the children are able to use individuality. ( pony beads, pipe cleaner, and tag board )