Lesson 2 - Exam practice
Test your knowledge
Work through these questions as you would in an exam. Answer the MCQ first, then write your answers to the written questions before revealing the mark scheme.
Section 1: Multiple choice
Select one answer per question. Instant feedback appears when you choose.
Question 1 of 5
What is the result of 01101001 + 00010111 in 8-bit binary?
01101001 (105) + 00010111 (23) = 10000000 (128). Add from right to left, carrying 1s where needed.
Question 2 of 5
An 8-bit addition produces a 9-bit result. What has occurred?
Overflow occurs when the result of an arithmetic operation is too large to store in the available bits. A 9th bit is generated, which cannot be held in an 8-bit register.
Question 3 of 5
What is the effect of a logical left shift of 2 places on the value 00001011?
Each left shift position multiplies by 2. Shifting left by 2 positions multiplies by 2² = 4. 00001011 (11) becomes 00101100 (44).
Question 4 of 5
Which of the following represents -14 in 8-bit two's complement?
14 = 00001110. Invert: 11110001. Add 1: 11110010. Two's complement of -14 is 11110010.
Question 5 of 5
A right shift of 3 is applied to 10110000 (176). What is the new denary value?
Right shift by 3 is equivalent to dividing by 2³ = 8. 176 ÷ 8 = 22. Result: 00010110 (22).
Section 2: Written questions
Write a full answer in your notebook or on paper before checking against the lesson notes.
Written question 1
Calculate 01011011 + 00101110. Show all column carries clearly. State whether overflow occurs and justify your answer.
4 marks
Written question 2
Show the two's complement representation of -99 in 8 bits. Explain each step.
4 marks
Written question 3
Explain why binary shifts are used in programs for multiplication and division, and identify one limitation of this approach.
4 marks