Centesimal Frame: Fractions as Decimal Fractions
Made by Nienhuis Montessori · shipped by Heutink International (Netherlands) About the maker
A metal frame used with the fraction circles to show how a fraction can be rewritten as a decimal. It is the bridge between two things a child has learned separately: that a whole can be cut into thirds, and that a whole can be cut into tenths and hundredths. The frame puts one over the other so a third stops being an alternative to 0.333 and starts being the same quantity written differently. Fraction circles sold separately. Metal, for ages 6 to 12.
“Children display a universal love of mathematics, which is par excellence the science of precision, order, and intelligence.”
The Centesimal Frame embodies Montessori's principle of bridging concrete experiences with abstract concepts. Through hands-on manipulation of this precise measuring tool, children internalize angular relationships before encountering formal geometry.
- Precise measurement and reading of angles from 0-90 degrees
- Understanding of angular relationships and geometric concepts
- Development of fine motor control and hand-eye coordination
- Application of mathematical concepts to practical life situations
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This material honors the child's need for exactness while supporting their natural mathematical mind. By engaging with real measurements in practical contexts, children develop both precision in movement and clarity of thought. The material's design allows for self-correction, fostering independence and confidence in mathematical exploration. It represents Montessori's vision of mathematics as a language for understanding the world, connecting everyday observations with geometric principles through purposeful activity.
How to present it
Follow the Montessori method of presentation for optimal child development.
Place the Centesimal Frame on a mat with a selection of geometric shapes, rulers, and paper. Ensure adequate lighting and a stable work surface. Have pencils and recording sheets available.
- 1
Demonstrate holding the frame steady against a corner or angle to be measured
Show how to align the baseline precisely with one edge before reading - 2
Guide the child to read the degree marking where the second edge crosses the scale
Use a pointer or pencil tip for accurate reading - 3
Practice measuring various angles found in the environment
Start with obvious right angles before progressing to acute and obtuse angles - 4
Introduce angle construction by drawing specific angles using the frame as a guide
Begin with common angles like 45° and 30° before attempting others - 5
Record measurements systematically on prepared sheets
Encourage estimation before measuring to develop angular sense
Every Child Is a Little Creator

Heritage
Since 1929

In classrooms
Around the world

European brands
Nienhuis, GAM, Educo

AMI approved
To the association standard

Centesimal Frame: Fractions as Decimal Fractions

