Formula 1 + 2x3 + 4x5 + 6x7 + +The parity of sum of 100x101 is ()

Formula 1 + 2x3 + 4x5 + 6x7 + +The parity of sum of 100x101 is ()

Formula 1 + 2x3 + 4x5 + 6x7 + +The parity of sum of 100x101 is (odd)
2×3,4×5,6×7…… 100 × 101 these are even numbers
Even addition is still even
One plus an even number is odd

1. 5 + 7 × 8 + 12 △ 4-2 = 205 + 7 × 8 + 12 △ 4-2 = 381 + 2 × 3 + 4 × 5 + 6 × 7 + 8 × 9 = 303

5+(7×8+12)÷4-2=20
5+7×(8+12)÷4-2=38
(1+2×3+4×5+6)×7+8×9=303

Add brackets to make the formula (1) 1 * 2 + 3 * 4 + 5 * 6 + 7 * 8 = 326 (2) 1 + 2 * 3 + 4 * 5 + 6 * 7 + 8 * 9 = 303

(1*2+3)*(4+5)*6+7*8=326
(1+2×3+4×5+6)×7+8×9=303

99 times 3 / 5 times 60%
4 / 5 times 18 + 82 times 80%

99 times 3 / 5 times 60%
=(100-1)x36
=100x0.36-0.36
=36-0.36
=35.64