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Arithmetic Relational And Logical Operations Edexcel

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Exam code:1CP2

What is an operator?

An operator is a symbol used to instruct a computer to perform a specific operation on one or more values
Examples of common operators include:
- Arithmetic
- Relational
- Logical (AND, OR and NOT)

Arithmetic Operators

There are a range of arithmetic operators that must be used in programming questions
The table below summarises each of the operators

Operator	Python
Addition	`+`
Subtraction	`-`
Multiplication	`*`
Division	`/`
Modulus (remainder after division)	`%`
Quotient (whole number division)	`//`
Exponentiation (to the power of)	`**`

To demonstrate the use of common arithmetic operators, three sample programs written in Python are given below
Comments have been included to help understand how the arithmetic operators are being used
- Arithmetic operators #1 – a simple program to calculate if a user-entered number is odd or even
- Arithmetic operators #2 – a simple program to calculate the area of a circle from a user-inputted radius
- Arithmetic operators #3 – a simple program that generates 5 maths questions based on user inputs and gives a score of how many were correctly answered at the end

Python code
`# -----------------------------------------------------------------------` `# Arithmetic operators #1` `# -----------------------------------------------------------------------` `# Get the user to input a number` `user_input = int(input("Enter a number: "))` `# if the remainder of the number divided by 2 is 0, the number is even` `if user_input % 2 == 0:` `print("The number is even.")` `else:` `print("The number is odd.")` `# -----------------------------------------------------------------------` `# Arithmetic operators #2` `# -----------------------------------------------------------------------` `# Get the radius from the user` `radius = float(input("Enter the radius of the circle: "))` `# Calculate the area of the circle` `area = 3.14159 * radius ** 2` `# Display the calculated area` `print("The area of the circle with radius",radius,"is",area)` `# ------------------------------------------------------------------------` `# Arithmetic operators #3` `# ------------------------------------------------------------------------` `# Set the score to 0` `score = 0` `# Loop 5 times` `for x in range(5):` `num1 = int(input("Enter the first number: "))` `operator = input("Enter the operator (+, -, ): ")` `num2 = int(input("Enter the second number: "))` `user_answer = int(input("What is "+str(num1)+str(operator)+str(num2)+"? "))` `# Check the answer and update the score` `if operator == '+':` `correct_answer = num1 + num2` `elif operator == '-':` `correct_answer = num1 - num2` `elif operator == '':` `correct_answer = num1 * num2` `if user_answer == correct_answer:` `score = score + 1` `else:` `print("Sorry that's incorrect.")` `print("Your score is:", score)`

Python code

# -----------------------------------------------------------------------
# Arithmetic operators #1
# -----------------------------------------------------------------------
# Get the user to input a number
user_input = int(input("Enter a number: "))

# if the remainder of the number divided by 2 is 0, the number is even
if user_input % 2 == 0:
print("The number is even.")
else:
print("The number is odd.")

# -----------------------------------------------------------------------
# Arithmetic operators #2
# -----------------------------------------------------------------------
# Get the radius from the user
radius = float(input("Enter the radius of the circle: "))

# Calculate the area of the circle
area = 3.14159 * radius ** 2

# Display the calculated area
print("The area of the circle with radius",radius,"is",area)

# ------------------------------------------------------------------------
# Arithmetic operators #3
# ------------------------------------------------------------------------
# Set the score to 0
score = 0

# Loop 5 times
for x in range(5):
num1 = int(input("Enter the first number: "))
operator = input("Enter the operator (+, -, *): ")
num2 = int(input("Enter the second number: "))
user_answer = int(input("What is "+str(num1)+str(operator)+str(num2)+"? "))

# Check the answer and update the score
if operator == '+':
correct_answer = num1 + num2
elif operator == '-':
correct_answer = num1 - num2
elif operator == '*':
correct_answer = num1 * num2

if user_answer == correct_answer:
score = score + 1
else:
print("Sorry that's incorrect.")

print("Your score is:", score)

Relational Operators & Logical Operations

There are a range of relational and logical operators that must be used in programming questions
The tables below summarise each of the operators

Relational Operators

Operator	Python
Equal to	`==`
Not equal to	`!=`
Less than	`<`
Less than or equal to	`<=`
Greater than	`>`
Greater than or equal to	`>=`

Logical Operators

Logical operators can be categorised into three
- AND
- OR
- NOT
Logical operators are always used alongside relational operators to form a comparison, some examples of this are:
1. If number > 5 AND number <10:
  print("Valid number")
2. If number <0 OR number >11:
  print("You are outside the range, try again")

Examples

Operator	Python
Addition	`sum = 2 + 2 # 4`
Multiplication	`sum = 3 * 4 # 12`
Modulus	`sum = 10 % 3 # 1`
Quotient	`sum = 10 // 3 # 3`
Exponentiation	`sum = 2 ** 2 # 4`
Equal to	`if 3 == 3: # True`
Not equal to	`if 5 != 6: # True`
Greater than or equal to	`if 10 >= 2: # True`
AND	`number = 10` `if number > 0 and number < 20:` `# True`

To demonstrate the use of common operators, three sample programs written in Python are given below
Comments have been included to help understand how the operators are being used
- Common operators #1 – a simple program that assigns Boolean values to two variables and outputs basic comparisons
- Common operators #2 – a simple program to output a grade based on a users score
- Common operators #3 – a simple program reads a text files and searches for an inputted score

Python code
`# -----------------------------------------------------------` `# Common operators #1` `# -----------------------------------------------------------` `# Assign a Boolean value to a and b` `a = True` `b = False` `# print the result of a and b` `print("a and b:", a and b)` `# print the result of a or b` `print("a or b:", a or b)` `# print the result of not a` `print("not a:", not a)` `# -----------------------------------------------------------` `# Common operators #2` `# -----------------------------------------------------------` `# Take input for the score from the user` `score = int(input("Enter the score: "))` `# Compare the score and output the corresponding grade` `if score >= 90 and score <= 100:` `print("Grade: A")` `elif score >= 80 and score < 90:` `print("Grade: B")` `elif score >= 70 and score < 80:` `print("Grade: C")` `elif score < 70:` `print("Fail")` `# -----------------------------------------------------------` `# Common operators #3` `# -----------------------------------------------------------` `# Open the file for reading` `file = open("scores.txt","r")` `# Set flags to false` `end_of_file = False` `found = False` `score = input("Enter a score: ")` `# While it's not the end of the file and the score has not been found` `while not end_of_file and not found:` `# read the line` `scores = file.readline().strip()` `# if the line equals the score` `if score == str(scores):` `found = True` `print("Score found")` `# if the line is empty` `if scores == "":` `end_of_file = True` `print("Score not found")` `file.close()`

Python code

# -----------------------------------------------------------
# Common operators #1
# -----------------------------------------------------------
# Assign a Boolean value to a and b
a = True
b = False

# print the result of a and b
print("a and b:", a and b)
# print the result of a or b
print("a or b:", a or b)
# print the result of not a
print("not a:", not a)

# -----------------------------------------------------------
# Common operators #2
# -----------------------------------------------------------

# Take input for the score from the user
score = int(input("Enter the score: "))

# Compare the score and output the corresponding grade
if score >= 90 and score <= 100:
print("Grade: A")
elif score >= 80 and score < 90:
print("Grade: B")
elif score >= 70 and score < 80:
print("Grade: C")
elif score < 70:
print("Fail")

# -----------------------------------------------------------
# Common operators #3
# -----------------------------------------------------------
# Open the file for reading
file = open("scores.txt","r")
# Set flags to false
end_of_file = False
found = False
score = input("Enter a score: ")
# While it's not the end of the file and the score has not been found
while not end_of_file and not found:
# read the line
scores = file.readline().strip()
# if the line equals the score
if score == str(scores):
found = True
print("Score found")
# if the line is empty
if scores == "":
end_of_file = True
print("Score not found")
file.close()

Computer Science GCES EDEXCEL