1 times 2 times 1 / 3 plus 2 times 3 times 1 / 4 all the way to 9 times 10 times 1 / 11

1 times 2 times 1 / 3 plus 2 times 3 times 1 / 4 all the way to 9 times 10 times 1 / 11

1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9+1/10
=(1/2+1/3+1/6)+(1/4+1/5+1/10)+1/7+1/8+1/9
=1+11/20+1/8+1/7+1/9
=1+27/40+1/9+1/7
=1+283/360+1/7
=1+2341/2520
=4861/2520
9 - (4861-2520) = needless to say
1*1\2+2*1\3+.+9*1\10=1-1\2+1-1\3+1-1\4+.1-1\10=9-(1\2+1\3+1\4+.1\10)

95×38+62÷195．

95×38+62÷195，=95×38+62×95，=95×（38+62），=95×100，=9500．

Simple operation of dividing 37 / 38 by 1 / 39

37/38÷1/39
=37/38×39
=37/38×（38+1）
=37+37/38
=37 and 37 / 38

The whole process 74 * 1042 / 37 * (- 9 / 37) / (- 521) - 38 * 36 / 37
74*1042/37*（-9/37）/（-521）-38*36/37

74*1042/37*（-9/37）/（-521）-38*36/37
=74/37*1042/(-521)*(-9)/37-38*36/37
=2*(-2)*(-9)/37-38*36/37
=36/37-36/37*38
=36/37*(1-38)
=36/37*(-37)
=-36