1 + 3 = 4 = 221 + 3 + 5 = 9 = 321 + 3 + 5 + 7 = 16 = 42 1+3+5+7+9+11+13+… +19=______ =______ 2.

1 + 3 = 4 = 221 + 3 + 5 = 9 = 321 + 3 + 5 + 7 = 16 = 42 1+3+5+7+9+11+13+… +19=______ =______ 2.

1+3+5+7+9+11+13+… +The common number of items is: (19-1) △ 2 + 1, = 18 △ 2 + 1, = 10; 102 = 100; that is: 1 + 3 + 5 + 7 + 9 + 11 + 13 + +19 = 100 = 102, so the answer is: 100, 10