2. Understanding error. (20 marks) For a 9-bit computer, the float number is stored as a 1-bit sign, 4-bit signed exponent, and 4-bit of mantissa part, as shown in the diagram below. (1) Fill numbers into the diagram to show how a base-10 number -4.5 is stored. Show your reasoning carefully. (10 marks) (2) Can a based-10 number of 2.1 be represented accurately? If not, what is the smallest error? Show your reasoning carefully. (10 marks)