See, that was easy. Don't doubt yourself!

Back to our sandwich software, we want to calculate the total cost for a customer when they purchase multiple quantities of the same product.

Let's say a group of 4 friends go out and purchase the same sandwich for lunch. Instead of doing this:

Integer sandwichPrice = 7;
Integer totalPrice = sandwichPrice + sandwichPrice + sandwichPrice + sandwichPrice;

We can use multiplication to make this more succinct. Apex uses the * operator for multiplication. Let’s try it out:

Integer sandwichPrice = 7;
Integer quantity = 4;
Integer totalCost = sandwichPrice * quantity;
// totalCost is now set to 28

Let’s say another group of 3 friends wants to split their bill evenly. Apex provides the / operator for division. We can use this to divide the total price by the number of friends. The code would look something like this:

Integer totalPrice = 120;
Integer numberOfFriends = 3;
Integer pricePerFriend = totalPrice / numberOfFriends;
// pricePerFriend is now 40

Here are a few more examples of multiplication and division in action.

Integer yearlyRentCost = 12 * 1000;
Integer monthlyRentCost = yearlyRentCost / 12; //get 1000 again

Integer hourlyRate = 20;
Integer hoursPerWeek = 40;
Integer weeklyPay = hourlyRate * hoursPerWeek;