1st row:
1 = 1
2nd row:
1+3=4
3rd row:
1+ 3 + 5 = 9
4th row:
1+ 3 + 5 + 7 = 16
5th row:
1+ 3 + 5 + 7 + 9 =?
6th row:
1+ 3 + 5 + 7 + 9 + 11 =?
7th row:
1+ 3 + 5 + 7 + 9 + 11 + 13 =?
b). What is the sum for the 20th row? for the 50th row?