19. Represent the following decimal numbers in binary using 8-bit signed magnitude, one's complement, two's complement, and excess-127 representations: a) 89 b)-89 22. What decimal value does the 8-bit binary number 10110100 have if: a) it is interpreted as an unsigned number? b) it is on a computer using signed-magnitude representation? c) it is on a computer using one's complement representation? d) it is on a computer using two's complement representation? e) it is on a computer using excess-127 representation? 25. Using a "word" of 4 bits, list all of the possible signed binary numbers and their decimal equivalents that are representable in: a) Signed magnitude b) One's complement c) Two's complement 51. Show how each of the following floating-point values would be stored using IEEE-754 single precision (be sure to indicate the sign bit, the exponent, and the significand fields): a) 12.5 b)-1.5 c) 0.75 d) 26.625 56. a) The ASCIl code for the letter A is 1000001, and the ASCII code for the letter a is 1100001. Given that the ASCII code for the letter G is 1000111, without looking at Table 2.7, what is the ASCIl code for the letter g? b) The EBCDIC code for the letter A is 1100 0001, and the EBCDIC code for the letter a is 1000 0001. Given that the EBCDIC code for the letter G is 1100 0111, without looking at Table 2.7, what is the ASCI code for the letter g? code for the letter A is 1000001, and the ASCIl code for the letter a is 1100001. Given that the ASCI code for the letter Q is 1010001, without looking at Table 2.7, what is the ASCl code for the letter