Algebra - Toothpick patterns

Do Now: What is the smallest number of tooth picks to make 2 squares?

Problem:

Ripeka and Jan were sitting around playing with toothpicks when Ripeka started to make a pattern of  squares. 

How many toothpicks would she need to make a pattern like this that had 9 squares?

How many toothpicks do you need to make 3 squares? 4 squares?

Can you predict how many you will need for 5? Why do you think that?

Can you see a pattern in the number of toothpicks you need? Describe this?

In your own words,  write down using their own words the rule for finding the number of toothpicks.

Source: NZ Maths