Express the following numbers in dot patterns:
21

Answer

To express the number 21 in dot patterns, we will follow these steps:

### Step-by-Step Solution:

1. **Start with the Number**: We need to express the number 21 using dots.

2. **Draw the Dots**: Begin drawing dots one by one until you reach a total of 21 dots.
- You can group them in rows for better visualization. For example, you can create rows of 5 dots each.

3. **Count the Dots**: After drawing, count the dots to ensure you have exactly 21 dots.
- You can count them in groups (like counting by fives) to make it easier.

4. **Pair the Dots**: To check if the number is odd or even, start pairing the dots.
- Pair them in groups of 2.

5. **Identify Odd or Even**: After pairing, if there is one dot left without a pair, then the number is odd.
- If all dots are paired with none left over, then the number is even.

### Final Representation:
- You will have a total of 21 dots represented visually, and you will notice that one dot remains unpaired, confirming that 21 is an odd number.