Cover up II

This task is about showing how to find out how many counters are covered on an array.
 
For the questions below there are 10 × 10 (100) counters and some have been covered.
 
a) Show how to work out how many counters have been covered.
 
 
 
 
 

Answer: __________  

b) Show how to work out how many counters have been covered.

 
 
 
 
 

Answer: __________  

 


 
c) Show how to work out how many counters have been covered.
 
 
 
 
 

Answer: __________