Overview: 3 questions will be solved this time.Among them
           ☆3 arithmetic calculations

[1/3 Formula]
    Work: Calculate the value of equation 1*2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10 .
    Question type: Mathematical calculation
    Solution:
          1*2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10
        =2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10
        =2+6+3*4+4*5+5*6+6*7+7*8+8*9+9*10
        =2+6+12+4*5+5*6+6*7+7*8+8*9+9*10
        =2+6+12+20+5*6+6*7+7*8+8*9+9*10
        =2+6+12+20+30+6*7+7*8+8*9+9*10
        =2+6+12+20+30+42+7*8+8*9+9*10
        =2+6+12+20+30+42+56+8*9+9*10
        =2+6+12+20+30+42+56+72+9*10
        =2+6+12+20+30+42+56+72+90
        =8+12+20+30+42+56+72+90
        =20+20+30+42+56+72+90
        =40+30+42+56+72+90
        =70+42+56+72+90
        =112+56+72+90
        =168+72+90
        =240+90
        =330
    Answer:1*2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10=330
[2/3 Formula]
    Work: Calculate the value of equation 30-29-28+27+26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7 .
    Question type: Mathematical calculation
    Solution:
          30-29-28+27+26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =1-28+27+26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =-27+27+26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =0+26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =1-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =-23+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =0+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =1-20+19+18-17-16+15+14-13-12+11+10-9-8+7
        =-19+19+18-17-16+15+14-13-12+11+10-9-8+7
        =0+18-17-16+15+14-13-12+11+10-9-8+7
        =18-17-16+15+14-13-12+11+10-9-8+7
        =1-16+15+14-13-12+11+10-9-8+7
        =-15+15+14-13-12+11+10-9-8+7
        =0+14-13-12+11+10-9-8+7
        =14-13-12+11+10-9-8+7
        =1-12+11+10-9-8+7
        =-11+11+10-9-8+7
        =0+10-9-8+7
        =10-9-8+7
        =1-8+7
        =-7+7
        =0
    Answer:30-29-28+27+26-25-24+23+22-21-20+19+18-17-16+15+14-13-12+11+10-9-8+7=0
[3/3 Formula]
    Work: Calculate the value of equation 2+4+6+8+10+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23 .
    Question type: Mathematical calculation
    Solution:
          2+4+6+8+10+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =6+6+8+10+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =12+8+10+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =20+10+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =30+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =42+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =56+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =72+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =90+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =110+22+24-1-3-5-7-9-11-13-15-17-19-21-23
        =132+24-1-3-5-7-9-11-13-15-17-19-21-23
        =156-1-3-5-7-9-11-13-15-17-19-21-23
        =155-3-5-7-9-11-13-15-17-19-21-23
        =152-5-7-9-11-13-15-17-19-21-23
        =147-7-9-11-13-15-17-19-21-23
        =140-9-11-13-15-17-19-21-23
        =131-11-13-15-17-19-21-23
        =120-13-15-17-19-21-23
        =107-15-17-19-21-23
        =92-17-19-21-23
        =75-19-21-23
        =56-21-23
        =35-23
        =12
    Answer:2+4+6+8+10+12+14+16+18+20+22+24-1-3-5-7-9-11-13-15-17-19-21-23=12

Your problem has not been solved here? Please go to the Hot Problems section！