## How Many Under the Shell?

Hit **Start** to go to the problems page.

Okta will show you some bubbles, hide them under the shell, and then either add some or take some away. When Okta asks, "How many bubbles are under the shell?" enter your answer using the keypad.

If you need to see the demonstration again, click **Replay**. For a
different problem, click **New**. To select new parameters, click the **Set
Up** arrow.

**5**and choose

**–**(subtraction). This will give you subtraction problems that start with five bubbles. Then hit

**Start**.

You will be given a problem that looks like this: 5 – __ = __. (The number in the first blank will be filled in, but you'll need to find the number for the second blank.)

- What can you say about the two numbers that go in the blanks?