Explanation:
a) 7.5= 111.1×2°= 0.1111×2^3
which can also be written as
(1/2+1/4+1/8+1/16)×8
sign of mantissa:=0
Mantissa(9 bits): 111100000
sign of exponent: 0
Exponent(5 bits): 0011
the final for this is:011110000000011
b) -20.25= -10100.01×2^0= -0.1010001×2^5
sign of mantissa: 1
Mantissa(9 bits): 101000100
sign of exponent: 0
Exponent(5 bits): 00101
the final for this is:1101000100000101
c)-1/64= -.000001×2^0= -0.1×2^{-5}
sign of mantissa: 1
Mantissa(9 bits): 100000000
sign of exponent: 0
Exponent(5 bits): 00101
the final for this is:1100000000100101
