Oh sand tray. You are a wonderful tool.
When Caspar said he wanted to use the sand tray, I raced so fast to get it before he changed his mind, I didn't even clean the table. We had been painting, can you tell?
I had given up on the the sand tray, it was packed away in storage. Now it is back. I gave him the tray, he did the rest. First letters c and k, then numbers. He wanted to practice and repeat. The sand tray is now on his shelves so next time he doesn't have to ask.
I use Montessori Read and Write as my guide.
Sometimes I am asked about what actual Montessori materials we have at home. I like and recommend having sandpaper letters, numbers and a sand tray. I leave the lessons to the teachers at school but having these materials at home provides the child the opportunity to practice. And there is so much practising to be done right here, right now.