Here I present: ARITHMETIC BRAILLE’, Louis Braille’, Procedure for Writing Words, Music & Plainsong in Dots”, 1829.
INTRODUCTION.
The Braille’ mathematical slate (cubarithm) is a tactile device that allows blind and visually impaired individuals to perform mathematical calculations. It typically consists of a partitioned slate, and a set of weighted cubes, each embossed with Braille’ symbols. These slates are designed to help students learn and practice arithmetic, including addition, subtraction, multiplication, and division.
The Cubarithm was originally introduced by Oury in France in 1886. The Brannan slate was designed by R.E. Brannan of Summit, New Jersey. Brannan turned over his rights to the invention to American Printing House for the Blind (APH). Original set came with 100 cubes. APH began manufacturing the Brannan cubarithm slate in 1957 and it continues in the APH catalog to the present day. Cubarithm is marketed as a Braille’ mathematical tool for primary school students. 
