Arithmetic operators in R Programming - Mini Project: Build & Apply

Arithmetic Operators in R

📖 Scenario: You are helping a small shop owner calculate prices and discounts using simple math operations in R.

🎯 Goal: Build a small R script that uses arithmetic operators to calculate total price, discount amount, and final price after discount.

📋 What You'll Learn

Create variables with exact numeric values

Use arithmetic operators: +, -, *, /

Assign results to new variables

Print the final result

💡 Why This Matters

🌍 Real World

Calculating prices, discounts, and totals is common in shops, restaurants, and online stores.

💼 Career

Basic arithmetic operations are essential for data analysis, finance, and programming tasks.

1

Create initial price variables

Create two variables in R called price_item1 and price_item2 with values 120 and 80 respectively.

R Programming

# Create variables price_item1 and price_item2 with values 120 and 80
# Your code here

Hint

Use the assignment operator <- to assign values to variables.

2

Calculate total price

Create a variable called total_price that adds price_item1 and price_item2 using the + operator.

R Programming

price_item1 <- 120
price_item2 <- 80
# Calculate total_price by adding price_item1 and price_item2
# Your code here

Hint

Use total_price <- price_item1 + price_item2 to add the two prices.

3

Calculate discount amount

Create a variable called discount_rate with value 0.1 (10%). Then create a variable called discount_amount that multiplies total_price by discount_rate using the * operator.

R Programming

price_item1 <- 120
price_item2 <- 80
total_price <- price_item1 + price_item2
# Create discount_rate with 0.1
# Calculate discount_amount by multiplying total_price and discount_rate
# Your code here

Hint

Remember to assign discount_rate <- 0.1 and then multiply it with total_price.

4

Calculate final price and print

Create a variable called final_price that subtracts discount_amount from total_price using the - operator. Then print final_price using the print() function.

R Programming

price_item1 <- 120
price_item2 <- 80
total_price <- price_item1 + price_item2
discount_rate <- 0.1
discount_amount <- total_price * discount_rate
# Calculate final_price by subtracting discount_amount from total_price
# Print final_price
# Your code here

Hint

Use final_price <- total_price - discount_amount and then print(final_price).

Practice

1. Which of the following operators in R is used for multiplication?

easy

A. -

B. +

C. *

D. /

Solution

1. Step 1: Recall basic arithmetic operators in R

   In R, * is used for multiplication, + for addition, - for subtraction, and / for division.

2. Step 2: Identify the multiplication operator

   The operator * multiplies two numbers.

3. Final Answer:

   * -> Option C

4. Quick Check:

   Multiplication operator = * [OK]

Hint: Remember * means multiply in math and R [OK]

Common Mistakes:

• Confusing * with + or -
• Using / for multiplication
• Using ^ for multiplication

2. Which of the following is the correct syntax to calculate the remainder of 10 divided by 3 in R?

easy

A. 10 %% 3

B. 10 /% 3

C. 10 %/% 3

D. 10 % 3

Solution

1. Step 1: Understand remainder operator in R

   In R, the operator %% gives the remainder after division.

2. Step 2: Identify correct syntax for remainder

   10 %% 3 calculates remainder of 10 divided by 3, which is 1.

3. Final Answer:

   10 %% 3 -> Option A

4. Quick Check:

   Remainder operator = %% [OK]

Hint: Use %% for remainder, not % or /% [OK]

Common Mistakes:

• Using single % instead of %%
• Confusing integer division %/% with remainder %%
• Typing operators incorrectly like /%

3. What is the output of the following R code?

result <- 5 + 3 * 2
print(result)

medium

A. 16

B. 11

C. 10

D. 13

Solution

1. Step 1: Apply operator precedence in R

   Multiplication (*) has higher priority than addition (+), so 3 * 2 = 6 is calculated first.

2. Step 2: Calculate the expression

   Then add 5 + 6 = 11.

3. Final Answer:

   11 -> Option B

4. Quick Check:

   5 + (3 * 2) = 11 [OK]

Hint: Multiply before adding due to operator precedence [OK]

Common Mistakes:

• Adding before multiplying
• Ignoring operator precedence
• Calculating 5 + 3 first

4. Identify the error in this R code snippet:

value <- 10 %/ 3
print(value)

medium

A. Syntax error due to incorrect operator

B. Runs correctly and prints 3

C. Runs correctly and prints 1

D. Runtime error due to division by zero

Solution

1. Step 1: Check the operator used

   The operator %/ is not valid in R. Integer division uses %/%.

2. Step 2: Identify the error type

   Using %/ causes a syntax error because R does not recognize it.

3. Final Answer:

   Syntax error due to incorrect operator -> Option A

4. Quick Check:

   Integer division operator is %/% not %/ [OK]

Hint: Use %/% for integer division, not %/ [OK]

Common Mistakes:

• Typing %/ instead of %/%
• Confusing remainder %% with integer division
• Expecting output despite syntax error

5. You want to calculate the integer division and remainder of 17 divided by 4 in R. Which code correctly assigns both results to variables int_div and rem?

hard

A. int_div <- 17 %/ 4rem <- 17 %% 4

B. int_div <- 17 %% 4rem <- 17 %/% 4

C. int_div <- 17 / 4rem <- 17 % 4

D. int_div <- 17 %/% 4rem <- 17 %% 4

Solution

1. Step 1: Recall operators for integer division and remainder

   Integer division uses %/% and remainder uses %% in R.

2. Step 2: Match operators to variables

   int_div <- 17 %/% 4 correctly assigns integer division result (4).
   rem <- 17 %% 4 correctly assigns remainder (1).

3. Final Answer:

   int_div <- 17 %/% 4; rem <- 17 %% 4 -> Option D

4. Quick Check:

   Integer division %/% and remainder %% used correctly [OK]

Hint: Use %/% for int division, %% for remainder [OK]

Common Mistakes:

• Swapping operators for int division and remainder
• Using invalid operator %/
• Using / instead of %/% for integer division