 
 <translate> The total of seven numbers = 7X21 = 147
The total of first 3 and last 3 numbers is = 3 X 19+3 X 23 = 126
So, the middle number is (147 - 126 ) = 21
The final answer: (E). <ibo> Ọnụ ọgụgụ nke nọmba asaa = 7X21 = 147 Nchịkọta nke nọmba 3 mbụ na nke ikpeazụ bụ = 3 X 19 + 3 X 23 = 126 N'ihi ya, nọmba dị n'etiti bụ (147 - 126 ) = 21 Azịza ya bụ: (E). 