Abacus
Abacus is the oldest tool used for mathematical calculations. Abacus is probably the simplest instrument still in use to assist computation. Decimal numbers are represented by the position of beads on wire in a frame in which beads move up and down. It was discovered in china some 5000 Years ago.
Slide rule
The slide rule one of the most important mathematical innovation of the modern era is 400 years old. Jost Burgi, a Swiss astronomer was instrumental in devising it.
A slide rule is an instrument, which is used for rapid, through approximate calculations. Two scales are calibrated identically so that on each, the distance from 1 point to any point on the scale is proportional to the logarithm of the number represented by that point. It works on the principal of logarithm. It is a convenient tool for carrying out multiplication and division.
Mathematical calculating Machine
A mechanical calculating machine has a system of toothed-wheels inside it, which make the calculations possible. Addition and multiplication are done by turning the handle forward, while subtraction and division are achieved by turning if backward
Tools used to measure The Lengths
The different tools used for measuring lengths are: ruler, vernier calipers, micrometer, tape, curvimeter, etc.
Ruler
It is a kind of strip made of wood or plastic or metal, marked in inches on one side and in centimeters on the other side.
Vernier calipers
Vernier calipers are a metallic tool, which has a vernier scale and main scale marked in centimeters and inches. It can measure lengths with an accuracy of 0.01 of a millimeter
Tape
It is a long flexible plastic tape marked with a scale on it
Micrometer
It is an instrument for measuring accurately dimensions or separations. It is generally used to measure the diameters of wires or spherical balls with an accuracy of 0.01 mm
Curvimeter
The curvimeter is an instrument used to measure the distance along a curve or on a map
Protractor
A device used to measure angles in degrees. It is usually semicircular and marked off in degrees along the semicircle edge.
Set-squares
A pair of triangular shapes made of plastic. One triangle has the shape of isosceles right triangle and the other has the shape of a right angled triangle with other two angles of 600 and 300
Pantograph
A pantograph is an instrument used for duplicating geometrical shapes to a reduced or enlarged sale on a sheet of paper.
Planimeter
It is a simple integrating instrument for measuring the area of a regular or irregular plane surface. It consists of two hinged arms: one is kept free and the other is traced around the boundary of the area.
