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Past Paper Questions Jan 2011 3 (a) Calculate the denary value of the 8-bit binary number 10010111. You must show your working. 128 64 32 16 1 0 0 1 0 128 + 1 1 1 16 151 [2] June 2011 6 (a) Convert the hexadecimal number 6A to denary. You must show your working. 6 = 0110 A = 1010 therefore 128 64 32 16 0 1 1 0 64+ 32 + 8 1 8 4 0 + 2 1 2 6A = 01101010 1 0 = 106 ............................................................................................................................................. [2] (b) Convert the hexadecimal number 6A to binary. 6 = 0110 A = 1010 therefore 6A = 01101010 ............................................................................................................................................. [2] (c) Convert the binary number 00111101 to hexadecimal. 0011 = 3 1101 = D 3D ............................................................................................................................................. [2] (d) Explain why hexadecimal numbers are often used to represent binary numbers. As a short hand for binary so that we will make less mistakes when writing long binary numbers. ............................................................................................................................................. [2] 1