(1+1/2)*(1+1/4)*(1+1/5)*…… *(1+1/10)*(1-1/3)*(1-1/5)*(1-1/6)*…… *(1-1 / 9) how to calculate easily?

(1+1/2)*(1+1/4)*(1+1/5)*…… *(1+1/10)*(1-1/3)*(1-1/5)*(1-1/6)*…… *(1-1 / 9) how to calculate easily?

(1+1/2)*(1+1/4)*(1+1/6)*…… *(1+1/10)*(1-1/3)*(1-1/5)*(1-1/7)*…… *(1-1 / 9) = 3 / 2 × 5 / 4 × 7 / 6 × 9 / 8 × 11 / 10 × 2 / 3 × 4 / 5 × 6 / 7 × 8 / 9 = 3 / 2 × 2 / 3 × 5 / 4 × 4 / 5 × 7 / 6 × 6 / 7 ×× 9 / 8 × 8 / 9 × 11 / 10 = 11 / 10, the first part denominator is 2, 4, 6, 8, 10

(1 + 1 / 2) × (1 + 1 / 4) × (1 + 1 / 6) ×... × (1 + 1 / 10) × (1-1 / 3) × (1-1 / 5) ×... × (1-1 / 9) simple operation
Is it 11 / 10? It seems to have to be split

Original formula = 3 / 2 × 5 / 4 × 7 / 6 × ×9/8×11/10
×2/3×4/5×6/7×…… ×8/9
=11／10
3 / 2 and 2 / 3 are divided into 1 9 / 8 and 8 / 9 are divided into 1
That leaves the last 11 / 10 in the first line

[(2 / 15 + 3 / 49) × 15-1] × 4.90.85 × 102-3.32.3 × [17 + 3 and 1 / 5 ÷ (1.9-3 / 10)]
We look forward to the space in the middle, don't do it together

[(2 / 15 + 3 / 49) × 15-1] × 4.9
=（2+45/49-1）x4.9
=1x4.9+45/49x4.9
=4.9+4.5
=9.4
0.85×102-3.3
=0.85x100+0.85x2-3.3
=85+1.7-3.3
=83.4
2.3 × [17 + 3 and 1 / 5 (1.9-3 / 10)]
=2.3x(17+16/5÷16/10)
=2.3x(17+2)
=2.3x19
=2.3x20-2.3
=46-2.3
=43.7
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