Arithmetic operators in R Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of mixed arithmetic operations

What is the output of this R code snippet?

R Programming

result <- 5 + 3 * 2^2 - 4 / 2
print(result)

A [1] 11

B [1] 12

C [1] 14

D [1] 15

💡 Hint

Remember the order of operations: exponentiation, multiplication/division, addition/subtraction.

The expression evaluates as 5 + 3 * (2^2) - 4 / 2 = 5 + 3 * 4 - 2 = 5 + 12 - 2 = 15.

❓ Predict Output

intermediate

Result of integer division and modulus

What is the output of this R code?

R Programming

a <- 17
b <- 5
cat(a %/% b, a %% b)

A 3 2

B 2 3

C 3 3

D 2 2

💡 Hint

Integer division %/% gives quotient, modulus %% gives remainder.

17 divided by 5 is 3 with remainder 2, so output is '3 2'.

🔧 Debug

advanced

Identify the error in arithmetic expression

What error does this R code produce?

R Programming

x <- 10
y <- 0
z <- x / y
print(z)

A [1] Inf

B NaN

C Error: division by zero

D 0

💡 Hint

Check how R handles division by zero with numeric values.

In R, dividing a positive number by zero returns Inf (infinity), not an error.

❓ Predict Output

advanced

Output of combined arithmetic and logical operators

What is the output of this R code?

R Programming

a <- 4
b <- 2
result <- (a > b) + (b == 2) * 3
print(result)

A [1] 5

B [1] 3

C [1] 4

D [1] 1

💡 Hint

Logical TRUE is 1 and FALSE is 0 in arithmetic operations.

a > b is TRUE (1), b == 2 is TRUE (1), so result = 1 + 1*3 = 4.

🧠 Conceptual

expert

Number of elements in a vector after arithmetic recycling

Given the code below, how many elements does the resulting vector have?

R Programming

v1 <- c(1, 2, 3, 4, 5)
v2 <- c(10, 20)
result <- v1 + v2

A 2

B 5

C 10

D Error due to length mismatch

💡 Hint

R recycles shorter vectors to match the length of longer vectors.

v2 is recycled to length 5: (10,20,10,20,10), so result length is 5.

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