Rock wall

This task is about working out how many rocks are in a wall.
brick-wall.png
This farmer has made a rock wall.

Question 2Change answer

a)  This rock wall is 7 rocks wide and 5 rocks high.
     How many rocks are in the wall?  

Question 2Change answer

b)  The farmer wanted to make the wall higher. He added 3 more rows.
     i)    How many more rocks did he use?  
     ii)   What is the length of the wall now? 
     iii)  What is the height of the wall now? 
     iv)  How many rocks are in the wall now?