🔢 Your first calculator in Lua — learn to program from scratch

📘 Level: Beginner

🧠 You will learn:

• use variables

• read user input

• work with numbers

• apply conditions (if, elseif, else)

🚀 What we will do

In this task, you will create simple calculator, which can add, subtract, multiply and divide two numbers. Everything will happen in the terminal — as in classic console utilities.

🔧 Preparation

You can write code directly in the browser, for example here:
👉 https://replit.com/languages/lua

🧱 Step 1: Get input

We will ask the user to enter two numbers and an operation sign:

print("Enter the first number:")
local a = io.read("*n")

print("Enter the second number:")
local b = io.read("*n")

print("Enter operation (+, -, *, /):")
local op = io.read()

🧮 Step 2: Perform the operation

Now we process the input and calculate the result:

if op == "+" then
  print("Result: " .. (a + b))
elseif op == "-" then
  print("Result: " .. (a - b))
elseif op == "*" then
  print("Result: " .. (a * b))
elseif op == "/" then
  if b ~= 0 then
    print("Result: " .. (a / b))
  else
    print("You can't divide by zero!")
  end
else
  print("Unknown operation")
end

✅ Verification

Test the calculator:

• 10, 5, + → 15

• 10, 0, / → warning about division by zero

💡 Additional ideas

• Add a restart of the calculator after completion

• Make a simple menu before you start

• Support fractional numbers

🐾 What's next

Now you have your first console utility on Lua! This is a great base for the next step — creating mini-applications or even simple games.

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