When calculating the following questions, those who can be easily calculated must be easily calculated! (4 / 5 + 1 / 2) × 26 / 27 [5 / 6 - (1 / 2-1 / 3)] × 2 / 50

When calculating the following questions, those who can be easily calculated must be easily calculated! (4 / 5 + 1 / 2) × 26 / 27 [5 / 6 - (1 / 2-1 / 3)] × 2 / 50

(4/5+1/2)÷26/27[5/6-(1/2-1/3)]×2/50
=13/10×27/26(5/6-1/6)×1/25
=27/20×2/3×1/25
=9/250

How to calculate 1 / 1 × 1 / 2 + 1 / 2 × 1 / 3 + 1 / 3 × 1 / 4 + 1 / 4 × 1 / 5 + 1/49×1/50

1/1×1/2＋1/2×1/3＋1/3×1/4＋1/4×1/5+…… 1/49×1/50
=(1-1/2)+(1/2-1/3)+.+(1/49-1/50)
=1-1/50
=49/50

12+（13+23）+（14+24+34）+… +（150+250+350+… +4850+4950）．

The original formula is 12 + 1 + 23 + 1 + 2 + 34 + +1+2+… +4950=12+22+32+… +492=1+2+… +492=12252．

Simple operation: (27.1-27.1 * 0.8) / 0.2

(27.1-27.1*0.8)/0.2
=27.1*(1-0.8)/0.2
=27.1*0.2/0.2
=27.1