The operations of an electronic calculator are not only very quick, they are also very basic. Most of the calculations are done using simple addition and subtraction, and a number system which has only two numbers, 0 and 1.

This binary (two-state) number system is used in calculators and other electronic devices, because they operate on a system of electronic switches, which at any time can only be in one of two states; off or on. In the Binary code, ‘off is represented by 0, and ‘on’ by 1.

The calculator keyboard uses our usual (decimal) numbers, from 0 up to 9, on its keys, but when a key is pushed down, the calculator understands this in the binary equivalent, which is fed through a ‘switch point’ situated under the key, and from there into the heart of the calculator – the ‘chip’.

This is a tiny integrated circuit, an incredible network of electronic components in a piece of Silicon, itself smaller than a Do stage stamp.

The chip carries out the binary operations at the speed of light, and its answers are sent back to the display, and its answers are sent back to the display. The Calculator converts binary into decimal again, using a ‘decoder’ (a circuit based on switches),and these decimals appear on the display panel, using LED, or light emitting diode, segments.

The space for each unit on the display has seven such segments, plus a decimal point, and each LED gives off a reddish glow when required. Different combinations of these segments light up any decimal number from 0 up to 9, as the chip instructs through the switching circuit.

The chip adds in the standard binary way: 0+1 = 1; 0+) = 0’ and 1=1 = 0 (equivalent of 2). And it subtracts by reversing this procedure.

The operations of multiplication and division are carried out by continued addition and subtraction, respectively. For example, to multiply 43 by 17, the calculator adds 43 seventeen times. This may seem show to us, but electronically the answer is arrived at almost immediately.

Just try dividing 1,089 by 33, and see how long you take! How would the calculator solve this one? And because it works electronically, it can do harder sums in about the same amount of time. It would divide 582.31 by 34.9 as soon as add two and two!

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