Arithmetic operators in MATLAB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of mixed arithmetic operations

What is the output of the following MATLAB code?

MATLAB

a = 5;
b = 3;
c = a^2 - 4*b + 7;
disp(c);

A 19

B 18

C 25

D 20

💡 Hint

Remember the order of operations: powers first, then multiplication and subtraction.

The code calculates 5^2 - 4*3 + 7 = 25 - 12 + 7 = 20.

❓ Predict Output

intermediate

Division and modulus output

What is the output of this MATLAB code snippet?

MATLAB

x = 17;
y = 5;
q = floor(x / y);
r = mod(x, y);
disp([q, r]);

A [4 1]

B [3 1]

C [3 2]

D [4 2]

💡 Hint

Use floor division for quotient and mod for remainder.

17 divided by 5 is 3.4. Floor division gives 3.

Remainder is 17 - 5*3 = 2.

So output is [3 2].

❓ Predict Output

advanced

Result of element-wise vs matrix multiplication

What is the output of this MATLAB code?

MATLAB

A = [1 2; 3 4];
B = [2 0; 1 3];
C = A .* B;
D = A * B;
disp(C);
disp(D);

A

[2 0; 3 12]
[4 6; 10 12]

B

[2 0; 3 12]
[2 0; 1 3]

C

[3 2; 4 7]
[4 6; 10 12]

D

[3 2; 4 7]
[2 0; 1 3]

💡 Hint

Remember that .* is element-wise multiplication and * is matrix multiplication.

Element-wise multiplication multiplies each element individually:

C = [1*2 2*0; 3*1 4*3] = [2 0; 3 12]

Matrix multiplication:

D = [1*2+2*1 1*0+2*3; 3*2+4*1 3*0+4*3] = [4 6; 10 12]

❓ Predict Output

advanced

Output of combined arithmetic and logical operations

What is the output of this MATLAB code?

MATLAB

x = 4;
y = 7;
z = (x > 3) + (y < 5) * 10;
disp(z);

A 11

B 1

C 10

D 0

💡 Hint

Logical expressions return 1 for true and 0 for false. Multiplication has higher precedence than addition.

(x > 3) is true (1), (y < 5) is false (0).

Multiplication has higher precedence: 0 * 10 = 0, then 1 + 0 = 1.

❓ Predict Output

expert

Output of chained arithmetic with parentheses

What is the output of this MATLAB code?

MATLAB

a = 2;
b = 3;
c = 4;
d = a + b * c ^ a - (b + c) * a;
disp(d);

A 36

B 10

C 2

D -4

💡 Hint

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

Step by step:
c ^ a = 4^2 = 16
b * 16 = 3 * 16 = 48
(b + c) * a = (3 + 4) * 2 = 14
a + 48 - 14 = 2 + 48 - 14 = 36

Practice

1. Which arithmetic operator in MATLAB is used to multiply two numbers?

easy

A. +

B. -

C. *

D. ^

Solution

1. Step 1: Identify multiplication operator

   In MATLAB, the symbol * is used to multiply two numbers.

2. Step 2: Confirm other operators

   + is addition, - is subtraction, and ^ is power.

3. Final Answer:

   * -> Option C

4. Quick Check:

   Multiplication = * [OK]

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

Common Mistakes:

• Confusing * with + or -
• Using ^ for multiplication
• Forgetting * is needed for multiply

2. Which of the following is the correct MATLAB syntax using the power operator to calculate 5 raised to the power 3?

easy

A. 5^3

B. 5**3

C. power(5,3)

D. 5^^3

Solution

1. Step 1: Identify power operator syntax

   In MATLAB, the caret symbol ^ is used for powers, so 5^3 is correct.

2. Step 2: Check other options

   5**3 and 5^^3 are invalid syntax. power(5,3) is a function but not an operator.

3. Final Answer:

   5^3 -> Option A

4. Quick Check:

   Power operator = ^ [OK]

Hint: Use ^ for powers, not ** or ^^ [OK]

Common Mistakes:

• Using ** like other languages
• Typing ^^ by mistake
• Confusing function with operator

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

a = 10; b = 3; c = a / b;

medium

A. 3.3333

B. 3

C. 7

D. 13

Solution

1. Step 1: Understand division operation

   Variable a is 10, b is 3, so c = a / b divides 10 by 3.

2. Step 2: Calculate division result

   10 divided by 3 equals approximately 3.3333 in MATLAB.

3. Final Answer:

   3.3333 -> Option A

4. Quick Check:

   10 / 3 = 3.3333 [OK]

Hint: Division gives decimal result unless integers used carefully [OK]

Common Mistakes:

• Rounding to 3
• Adding instead of dividing
• Confusing division with subtraction

4. Find the error in this MATLAB expression:

result = 4 + * 5;

medium

A. Wrong operator for addition

B. Missing operand before *

C. Extra semicolon

D. No error

Solution

1. Step 1: Analyze the expression syntax

   The expression 4 + * 5 has two operators + and * without a number between them.

2. Step 2: Identify missing operand

   There should be a number between + and *, but it is missing, causing a syntax error.

3. Final Answer:

   Missing operand before * -> Option B

4. Quick Check:

   Operators need numbers between them [OK]

Hint: Operators must have numbers on both sides [OK]

Common Mistakes:

• Leaving out numbers between operators
• Thinking semicolon causes error
• Using wrong operator symbols

5. You want to calculate the expression (2 + 3) ^ 2 - 4 * 5 in MATLAB. Which code correctly computes this?

hard

A. 2 + (3 ^ 2 - 4) * 5

B. 2 + 3 ^ 2 - 4 * 5

C. (2 + 3) ^ (2 - 4) * 5

D. (2 + 3) ^ 2 - 4 * 5

Solution

1. Step 1: Understand operator precedence and parentheses

   The expression (2 + 3) ^ 2 - 4 * 5 means add 2 and 3 first, then square, then subtract 4 times 5.

2. Step 2: Check each option

   (2 + 3) ^ 2 - 4 * 5 matches the original expression exactly. Others change order or grouping, giving different results.

3. Final Answer:

   (2 + 3) ^ 2 - 4 * 5 -> Option D

4. Quick Check:

   Use parentheses to keep order correct [OK]

Hint: Use parentheses to control math order [OK]

Common Mistakes:

• Ignoring parentheses
• Changing operator order
• Misplacing powers or multiplication