1.2 Logical operations

Question 1

What is a logical expression?

Answer 1

A BOOLEAN expression where the result is True or False.

Question 2

What do logical operators do?

Answer 2

They join together logical expressions.

Question 3

Name 4 logical operators.

Answer 3

1. AND
2. OR
3. XOR
4. NOT

Question 3

What is a truth table?

Answer 3

A method of showing the inputs and outputs of a logical operator.

Question 3

What represents true and false in a truth table?

Answer 3

True: 1
False: 0

Question 3

How does OR work? (2)

Answer 3

1. One input must be true for outcome to be true.
2. Represented by a “+”

Question 3

How does XOR work? (2)

Answer 3

1. One input must be true for outcome to be true, but no more than one outcome can be true for output to be true.
2. Represented by a “⊕”

Question 3

How does NOT work? (2)

Answer 3

1. Requires one input and the output is always opposite of input.
2. Represented by an ‘

Question 4

What is the order presence of the
these operators?

Answer 4

NOT → AND → OR

Question 4

How are logical operators used in computing?

Answer 4

1. Clearing Registers
2. Masking

Question 5

How are logical operators used in clearing registers?

Answer 5

A register can be cleared using an AND operation.

Question 6

How are logical operators used in masking? (2)

Answer 6

1. Using AND operators you can check to see if a certain bit in a sequence is a 1 or a 0.
2. Using OR operators you could
   set certain bits to one no matter what they were before.

Question 7

What are Boolean laws for?

Answer 7

Simplifying Boolean expressions.

Question 8

What is the commutative law?

Answer 8

Order is not important on either side of an operator.

Question 9

What is the identity law?

Answer 9

Gets rid of redundant data.

Question 9

What is the associative law?

Answer 9

The order of multiple consecutive AND or OR operators are unimportant.

Question 10

What is the distributive law?

Answer 10

This is how elements outside the brackets are distributed within the brackets.

Question 11

What is the complement law?

Answer 11

If one side of an OR operator contains the content of the other side, the more complex side can be removed.