Arithmetic operators in Go - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of integer division and modulo

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    a := 17
    b := 5
    fmt.Println(a / b)
    fmt.Println(a % b)
}

A

3
-2

B

3.4
2

C

3
0

D

3
2

💡 Hint

Remember that integer division in Go truncates the decimal part.

In Go, dividing two integers results in integer division, so 17 / 5 equals 3. The modulo operator % gives the remainder, so 17 % 5 equals 2.

❓ Predict Output

intermediate

Output of mixed float and integer arithmetic

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    var x float64 = 7.5
    var y int = 2
    fmt.Println(x / float64(y))
}

A 3

B 3.5

C 3.75

D Compilation error

💡 Hint

You need to convert the integer to float64 before division.

Go does not allow direct arithmetic between different types. Converting y to float64 allows floating-point division, so 7.5 / 2.0 equals 3.75.

❓ Predict Output

advanced

Output of complex arithmetic expression

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    a := 10
    b := 3
    c := 4
    result := a - b*c + b/b
    fmt.Println(result)
}

A -1

B 1

C 4

D 7

💡 Hint

Remember operator precedence: multiplication and division before subtraction and addition.

Operator precedence: * and / first (left-to-right). b*c = 3*4 = 12, b/b = 3/3 = 1. Then - and + left-to-right: 10 - 12 + 1 = -1.

❓ Predict Output

advanced

Output of arithmetic with negative numbers

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    x := -15
    y := 4
    fmt.Println(x / y)
    fmt.Println(x % y)
}

A

-3
-1

B

-3
-3

C

-3
1

D

-4
1

💡 Hint

In Go, integer division truncates toward zero and modulo has the same sign as the dividend.

Integer division truncates toward zero: -15 / 4 = -3. Modulo sign matches dividend: -15 % 4 = -15 - (-3)*4 = -15 + 12 = -3.

❓ Predict Output

expert

Output of arithmetic with mixed types and constants

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    const a = 5
    var b float64 = 2.5
    c := a * int(b)
    fmt.Println(c)
}

A 12.5

B 10

C Compilation error

D 7

💡 Hint

You must convert float64 to int before multiplication with int constant.

The constant a is int 5, b is float64 2.5. Converting b to int truncates to 2, so c = 5 * 2 = 10.

Practice

1. Which arithmetic operator in Go is used to find the remainder of a division?

easy

A. /

B. +

C. *

D. %

Solution

1. Step 1: Understand the remainder operation

   The remainder operator returns what is left after division.

2. Step 2: Identify the correct operator in Go

   In Go, the remainder operator is represented by the percent sign '%'.

3. Final Answer:

   % -> Option D

4. Quick Check:

   Remainder = % [OK]

Hint: Remainder uses % like in many languages [OK]

Common Mistakes:

• Confusing division / with remainder %
• Using * for remainder
• Using + for remainder

2. Which of the following is the correct way to write a multiplication operation in Go?

easy

A. a x b

B. a . b

C. a * b

D. a & b

Solution

1. Step 1: Recall Go's multiplication syntax

   Go uses the asterisk '*' symbol for multiplication.

2. Step 2: Check each option

   Only 'a * b' uses the correct multiplication operator.

3. Final Answer:

   a * b -> Option C

4. Quick Check:

   Multiplication = * [OK]

Hint: Use * for multiplication, not x or & [OK]

Common Mistakes:

• Using 'x' instead of '*'
• Using '.' or '&' for multiplication
• Confusing syntax with other languages

3. What is the output of this Go code?

package main
import "fmt"
func main() {
  a := 7
  b := 3
  fmt.Println(a / b)
}

medium

A. 2.3333333

B. 2

C. 3

D. 0

Solution

1. Step 1: Identify variable types and operation

   Both a and b are integers, so division is integer division.

2. Step 2: Calculate integer division result

   7 divided by 3 is 2.333..., but integer division drops decimals, so result is 2.

3. Final Answer:

   2 -> Option B

4. Quick Check:

   Integer division 7/3 = 2 [OK]

Hint: Integer division drops decimals, result is int [OK]

Common Mistakes:

• Expecting float result
• Confusing integer division with float division
• Using wrong operator

4. Find the error in this Go code snippet:

package main
import "fmt"
func main() {
  x := 10
  y := 0
  fmt.Println(x / y)
}

medium

A. Division by zero causes runtime panic

B. Syntax error: missing semicolon

C. Variable y is not declared

D. No error, prints 0

Solution

1. Step 1: Analyze the division operation

   The code divides x by y, where y is zero.

2. Step 2: Understand Go's behavior on division by zero

   Dividing by zero causes a runtime panic (error) in Go.

3. Final Answer:

   Division by zero causes runtime panic -> Option A

4. Quick Check:

   Division by zero = runtime panic [OK]

Hint: Never divide by zero; it crashes the program [OK]

Common Mistakes:

• Thinking it prints 0
• Expecting compile-time error
• Ignoring runtime panic

5. Given the Go code below, what is the output?

package main
import "fmt"
func main() {
  a := 15
  b := 4
  c := a % b
  d := a / b
  fmt.Println(c + d)
}

hard

A. 6

B. 3

C. 19

D. 4

Solution

1. Step 1: Calculate remainder c = a % b

   15 % 4 equals 3 because 4*3=12 and 15-12=3.

2. Step 2: Calculate integer division d = a / b

   15 / 4 equals 3 because integer division drops decimals.

3. Step 3: Add c + d

   3 + 3 equals 6.

4. Final Answer:

   6 -> Option A

5. Quick Check:

   15 % 4 = 3, 15 / 4 = 3, 3 + 3 = 6 [OK]

Hint: Add remainder and integer division results carefully [OK]

Common Mistakes:

• Miscomputing remainder
• Using float division instead of integer
• Adding wrong values