In a Montessori Math curriculum, after introducing Numerical Rods (buy here) at around two years of age, Sandpaper Numbers (buy here) are generally introduced next, where a child visually sees the number; then traces it, feeling it sensorially with a touch; and finally, learns the name of the symbol of the number. Sandpaper numbers is a sort of a mixture between a sensorial and a math activity since the child learns the symbol/numeral which represents the number with different senses such as touch, sight, and hearing, while learning the name of a number.
The best way to present sandpaper numbers is using a 3🅿️🌠Three Period Lesson: (for a detailed 3🅿️🌠 Lesson presentation, see a post here). Start with three numbers at a time, for example presenting numbers one through three:
In a Nutshell: (1P) This says ______. (2P) Will you show me ______? (3P) What is this?
- (1st P) Choose a number and while tracing that number with an index and third finger say: “This says 1. Would you please trace 1?"; "This says 2." ... etc. (You would emphasize on "says vs. is" because the written number is merely a symbol representing that numeral and not the actual quantity.)
- (2nd P) “Will you show me 1?... 2? ... 3?"
- (3rd P) “What is this?"
At 31 months, Adrian can complete the 3🅿️🌠 Lesson only with numbers one through three, showing and naming them correctly when asked even during the last Third Period: "What is this?" However, starting with a number four, he confuses to name the numbers correctly (the Third Period).
p.s. An update: by 34 months, Adrian could correctly complete the entire 3🅿️🌠 Period Lesson with numbers 1-10 with wooden numbers puzzle (see a post here). And by 35 months, Adrian could complete3🅿️🌠 Period Lesson also with spindles (see a post here).
I strongly believe that learning and play compliment each other, so we would play a game: while keeping the numbers visible, I would give simple and fun instructions:
"Place number three on your head."
"Turn number two upside down."
"Hide number one behind your back," and so forth ...
As an extension, offer a child to shade over the number with colorful crayons.
See here a video-post "🖐️Sandpaper 🔢 Numbers (Montessori 🔢 Math 101 🎥 Series 🎇 Curriculum)" which illustrates how you would you a 3 Period Lesson.
For more on Montessori Math Lessons, read here "Early Math" post, which explains briefly which Montessori materials are to be introduced first and in what order. Also, "Sandpaper Numbers Extension" post (read here ) offers different ideas on how to use marbles or crayons to keep sandpaper numbers interesting and captivating.