I recently came across a question from another Montessori educator about how you bring awareness to the fact that adding a zero to the end of a decimal number doesn’t change its value. I looked through my album and couldn’t find such a lesson or extension. I then thought back to how I have dealt with this in the classroom. When there was confusion or questions about it, we would pull out the Decimal Board. I would have the student write the number and place it in the appropriate places above and then have them lay out the beads and cubes. They could then concretely see that 4.2500 is the same as 4.5 because there would be no cubes for the zeroes. Usually they would see that they are the same but if they were still having difficulty, I would encourage them to write 4.25 and then put out the corresponding beads and cubes.
I wanted to share this extension with others who might find themselves in this place as well. I have recently posted the Decimal Fraction Accessories packet which include the decimal pinwheel and decimal fraction strips. You can find the Decimal Fraction Accessories packet here.