Find out how the Mechanical Addiator and Mechanical Multiplier work

The Mechanical Addiator is a compact arithmetic machine (or adding machine) that works by moving gear racks, using a stylus included in the kit. By moving the sliding racks, marked with arrows and numbers from 0 to 9, you can add and subtract numbers.

The Mechanical Multiplier is a flat hinge mechanism that accomplishes binary operations on numbers. By moving the dual slider, you can multiply and square numbers from 1 to 12, making the multiplication table fun.

Who invented the Mechanical Addiator and Mechanical Multiplier, and when?

The UGEARS Mechanical Addiator is a DIY wooden model kit based on an addiator that was invented by a St. Petersburg music teacher, Heinrich Kummer, in 1846. Its simple design and compact size made it a popular mathematical tool in its time. Today this simple, fun mechanism is part of UGEARS' outstanding STEM Lab collection.

The UGEARS Mechanical Multiplier is a fun wooden 3D puzzle based on a children's toy, “Consul the Educated Monkey,” invented in 1915 by William Henry Robertson, an American high school math teacher. Robertson applied for a patent for a toy that ingeniously uses a hinged mechanism to perform simple multiplication, designed "to stimulate children's interest in the study of numbers.”

Uses for The Mechanical Addiator and Mechanical Multiplier

The Mechanical Addiator is used to add and subtract numbers. To do this, the user enters a number value using the stylus, then uses the stylus to enter a second number. The device then shows the result of the desired mathematical operation, according to where the second number was entered (top row for addition, bottom row for subtraction). But the Addiator is not limited to addition and subtraction—you can also use it to multiply and divide.

The Mechanical Multiplier is a simple and interesting way to learn the “unloved” multiplication tables from 1 to 12, and to understand the simple principle of hinge-lever mechanisms. When the two sliders are moved to various numbers, you will see their product displayed in the window above.