Replace 
in each of the following by the correct number:
(a) 
(b) 
(c) 
(d) 
(e) 
(a) We can calculate the following as follows:
Hence,
28 is the required blank
(b) We can calculate the following as follows:
Hence,
16 is the required blank
(c) We can calculate the following as follows:
Hence,
12 is the required blank
(d) We can calculate the following as follows:
Hence,
20 is the required blank
(e) We can calculate the following as follows:
Hence,
3 is the required blank
13