Arithmetic operators in Go - Mini Project: Build & Apply

Arithmetic Operators in Go

📖 Scenario: You are helping a small shop calculate the total cost of items bought by a customer. You will use arithmetic operators to add, subtract, multiply, and divide numbers.

🎯 Goal: Build a Go program that uses arithmetic operators to calculate the total price after applying a discount and tax.

📋 What You'll Learn

Create variables for item price and quantity

Create a variable for discount percentage

Calculate the total price before discount

Calculate the discount amount using arithmetic operators

Calculate the final price after discount and tax

Print the final price

💡 Why This Matters

🌍 Real World

Calculating prices with discounts and taxes is common in shopping and billing systems.

💼 Career

Understanding arithmetic operators is essential for programming tasks involving calculations, finance, and data processing.

1

Create initial variables for price and quantity

Create two variables called price and quantity with values 50 and 3 respectively.

Go

package main

import "fmt"

func main() {
    // Create variables price and quantity
    // Your code here
}

Hint

Use := to create variables and assign values in Go.

2

Add a discount percentage variable

Add a variable called discountPercent and set it to 10 to represent a 10% discount.

Go

package main

import "fmt"

func main() {
    price := 50
    quantity := 3
    // Add discountPercent variable
    // Your code here
}

Hint

Remember to use := to declare and assign the variable.

3

Calculate total price and discount amount

Calculate the total price before discount as totalPrice by multiplying price and quantity. Then calculate the discount amount as discountAmount by multiplying totalPrice by discountPercent divided by 100.

Go

package main

import "fmt"

func main() {
    price := 50
    quantity := 3
    discountPercent := 10
    // Calculate totalPrice and discountAmount
    // Your code here
}

Hint

Use * for multiplication and / for division.

4

Calculate final price and print it

Calculate the final price as finalPrice by subtracting discountAmount from totalPrice and then adding 5% tax. Print the finalPrice using fmt.Println.

Go

package main

import "fmt"

func main() {
    price := 50
    quantity := 3
    discountPercent := 10
    totalPrice := price * quantity
    discountAmount := totalPrice * discountPercent / 100
    // Calculate finalPrice and print it
    // Your code here
}

Hint

Calculate tax as 5% of the discounted price and add it. Use fmt.Println to show the result.

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