Matchstick patterns II

This task is about completing and describing rules for growing patterns.
1 2 3
a) i) Here are the first three shapes in a pattern. Finish the table to show the number of matches you would need to make the next four shapes in the pattern.
 

Shape number

1

2

3

4

5

6

7

Number of matches

5

9

13

       
 

ii)

Use words or an equation to explain how you worked the pattern out.

 

 

 

 
 
1 2 3
b) i)  Finish the table to show the number of matches you would need to make the next four shapes in this pattern.
 

Shape number

1

2

3

4

5

6

7

Number of matches

3

6

8

       
   
ii)
 
Use words or an equation to explain how you worked the pattern out.