Use the rule

This task is about using rules to finish number patterns.
You are given rules to complete a series of number patterns.

Use each rule below to finish off the number patterns. The first one has been done for you.
a)  Use the rule: + 1
 
     5,  6, 7, 8, 9

Question 1Change answer

b)  Use the rule: + 3
     1, , , ,  

Question 1Change answer

c) Use the rule: - 2
     20, , , , 

Question 1Change answer

d) Use the rule: × 2
     1, , , ,