Modulo Operator

Part of the Fundamentals section of Coddy's Lua journey — lesson 13 of 90.

The modulo operator represented by the percent symbol %. This operator finds the remainder that's left over after dividing one number by another.

In Lua, the local keyword declares a local variable — one that only exists within the current block or scope. It's good practice to use local when you don't need a variable to be accessible everywhere in your program.

Here's how the modulo operator works:

result = 10 % 3    -- result is 1 (10 divided by 3 is 3 with remainder 1)
result = 15 % 4    -- result is 3 (15 divided by 4 is 3 with remainder 3)
result = 8 % 2     -- result is 0 (8 divided by 2 is 4 with no remainder)

One of the most practical uses of the modulo operator is determining if a number is even or odd. When you divide any number by 2, if the remainder is 0, the number is even. If the remainder is 1, the number is odd:

number = 7
remainder = number % 2    -- remainder is 1, so 7 is odd

number = 10
remainder = number % 2    -- remainder is 0, so 10 is even

Challenge

Easy

Check if a player's score is a multiple of 10 using the modulo operator. Create a variable called playerScore and assign it the value 85. Then use the modulo operator to find the remainder when dividing the score by 10, and store this result in a variable called remainder. Print the remainder value.

Cheat sheet

The modulo operator % finds the remainder after dividing one number by another:

result = 10 % 3    -- result is 1 (10 divided by 3 is 3 with remainder 1)
result = 15 % 4    -- result is 3 (15 divided by 4 is 3 with remainder 3)
result = 8 % 2     -- result is 0 (8 divided by 2 is 4 with no remainder)

Use modulo to check if a number is even or odd:

number = 7
remainder = number % 2    -- remainder is 1, so 7 is odd

number = 10
remainder = number % 2    -- remainder is 0, so 10 is even

Try it yourself

-- Create the playerScore variable and assign it the value 85
local playerScore = 85

-- TODO: Write your code here to calculate the remainder using modulo operator

-- Print the remainder
print(remainder)