The fundamental concept of digital signal operations includes addition, subtraction, multiplication and division etc. VLSI considers the performance of design based on area, power and speed. It also takes into account other parameters such as correctness, reliability and precision of results. The most challenging among all the arithmetic operations is multiplication. It is basically due to its wide application in digital signal processing to improve the quality of output signal. A novel approach of high speed multiplication is using Q-format and common sub-expression elimination can be achieved at the cost of reduced precision.