Three-Digit Subtraction Input/Output Tables

At an arcade, you use tickets to buy your favorite candy. Each candy bar costs120 tickets.On your first game, you earned215 tickets.Out of these tickets, you bought 1 candy bar. In the next game, you earned180 ticketsand bought 1 more candy bar. You played once more and earned350 tickets.Then you bought 1 more candy bar. How many tickets did you haveleft over after buying each candy?

How can we solve this problem? 🤔

We have to subtract **120 tickets **from each total! ✅

120 tickets is the cost of 1 candy.

Since we are subtracting the same number so many times, we can keep track of the number of tickets left in an **input/output table**.** **

Do you remember what an Input/Output table is? 🤓

Aninput/output tableis a table with2 columns - In and Out, where the numbers in the first column follow a commonruleto give numbers in the second column.

This is an input/output table. 👇

Let us fill this table according to our example.

✅ First we fill the **In column.**

Which numbers should go in there? 🤔

Correct! 😃

Our ins are going to be the tickets you earned for each game: 215, 180, 350.

Let’s put those in the “In” column:

✅ Now, let us find the **rule **for this table.

According to the problem, what should happen to each number in the first column? 🤓

That's right!

We **subtract 120 tickets **from each number, because this is how much a candy costs.

So, the **rule **for this input/output table is:

Subtract 120

✅ Now, let us fill the **Out column.**

In this case, the output will be the total tickets after you subtract 120.

We start with the first number.

215 - 120 = 95

Now, we’ll put 95 in the first “Out” spot.

Let’s do the next one!

180 - 120 = 60

Great! Now, put 60 in the second "Out" spot.

Can you do the last one?

Great job!! 😎

😃 Let’s try another example.

Here’s an input/output table:

✅ The **rule **is:

Subtract 312

Let’s try the first one together.

470 - 312 = 158

Let’s put 158 in the first “Out” spot.

Can you do the rest of them? 🤔

You got it!! 🤗

Great job on the lesson! 👏 Now, you can move on to the practice!

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