Flip a coin 2 times, how many outcomes

Step by step

The question

Question: A coin is flipped 2 times.

How many outcomes are there?

1 Count the choices

2 Draw a tree

3 Multiply

Each of the 2 flip 1 goes with 2 flip 2.

So we multiply: 2 × 2.

This is the counting principle: multiply the number of choices.

2 groups of 2: that is 2 times 2.

Careful!

We do not add the choices.

Every flip goes with every other one, so we multiply.

2 times 2 is 4.

So there are 4 outcomes.

4 Check

Let's check: we count the ends of the tree.

There are 4 ends, one for each.

So the answer is right!

Let's look back.

First: count the choices.

Then: draw a tree.

Then: multiply.

Last: check.