1 + 3 = 22 = 4, 1 + 3 + 5 = 32 = 9, 1 + 3 + 5 + 7 = 42 = 16, then, 1 + 3 + 5 + 7 + 9 + +99=______ .

1 + 3 = 22 = 4, 1 + 3 + 5 = 32 = 9, 1 + 3 + 5 + 7 = 42 = 16, then, 1 + 3 + 5 + 7 + 9 + +99=______ .

1+3+5+7+9+… +99 = 502 = 2500, so the answer is: 2500