Overview: 5 questions will be solved this time.Among them
           ☆5 arithmetic calculations

[1/5 Formula]
    Work: Calculate the value of equation 1+2+3+4+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1 .
    Question type: Mathematical calculation
    Solution:
          1+2+3+4+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1
        =3+3+4+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1
        =6+4+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1
        =10+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1
        =15+6+7+8+9+10+9+8+7+6+5+4+3+2+1
        =21+7+8+9+10+9+8+7+6+5+4+3+2+1
        =28+8+9+10+9+8+7+6+5+4+3+2+1
        =36+9+10+9+8+7+6+5+4+3+2+1
        =45+10+9+8+7+6+5+4+3+2+1
        =55+9+8+7+6+5+4+3+2+1
        =64+8+7+6+5+4+3+2+1
        =72+7+6+5+4+3+2+1
        =79+6+5+4+3+2+1
        =85+5+4+3+2+1
        =90+4+3+2+1
        =94+3+2+1
        =97+2+1
        =99+1
        =100
    Answer:1+2+3+4+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1=100
[2/5 Formula]
    Work: Calculate the value of equation (1*2*3+2*3*4+3*4*5+4*5*6+5*6*7)/3 .
    Question type: Mathematical calculation
    Solution:
          (1*2*3+2*3*4+3*4*5+4*5*6+5*6*7)/3
        =420/3
        =140
    Answer:(1*2*3+2*3*4+3*4*5+4*5*6+5*6*7)/3=140
[3/5 Formula]
    Work: Calculate the value of equation 9+99+999+9999+99999 .
    Question type: Mathematical calculation
    Solution:
          9+99+999+9999+99999
        =108+999+9999+99999
        =1107+9999+99999
        =11106+99999
        =111105
    Answer:9+99+999+9999+99999=111105
[4/5 Formula]
    Work: Calculate the value of equation 1*2*4+2*4*8+4*8*16-2-4-8-16 .
    Question type: Mathematical calculation
    Solution:
          1*2*4+2*4*8+4*8*16-2-4-8-16
        =2*4+2*4*8+4*8*16-2-4-8-16
        =8+2*4*8+4*8*16-2-4-8-16
        =8+8*8+4*8*16-2-4-8-16
        =8+64+4*8*16-2-4-8-16
        =8+64+32*16-2-4-8-16
        =8+64+512-2-4-8-16
        =72+512-2-4-8-16
        =584-2-4-8-16
        =582-4-8-16
        =578-8-16
        =570-16
        =554
    Answer:1*2*4+2*4*8+4*8*16-2-4-8-16=554
[5/5 Formula]
    Work: Calculate the value of equation 8*9*111111 .
    Question type: Mathematical calculation
    Solution:
          8*9*111111
        =72*111111
        =7999992
    Answer:8*9*111111=7999992

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