**16. What is a digital system ?**

A digital system is a system that stores data in a discrete way. The opposite is an analogue (US- analog) system, which stores the data in a continuous way. Usually, digital systems store the information in a binary way; that is, every bit of information can not have a value other than zero (off) or one (on).

**17. What is decimal number system ?**

Decimal is a term that describes the base-10 number system, probably the most commonly used number system. The decimal number system consists of ten single- digit numbers: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

**18. What is a demultiplexer ?**

Demultiplexer (or demux) is a device taking a single input and selecting signals of the output of the compatible mux, which is connected to the single input, and a shared selection line. A multiplexer is often used with a complementary demultiplexer on the receiving end.

**19. Explain the advantages of the K-Map method ?**

Good method for simplifying expression up to four variables.

Used for the logical simplification..

Used for both SOP and POS forms of reduction.

**20. What is Binary Number System ?**

The binary number system is a numbering system that represents numeric values using two unique digits (0 and 1). Mosting computing devices use binary numbering to represent electronic circuit voltage state, which considers 0 voltage input as off and 1 input as on.