-3. 5/9 - 2. 7/18 =

1)(7*(1/3))-(5*(1/4))=((7*3+1)/3)-((5*4+1)/4)=(22/3)-(21/4)=((22/3)*(4/4))-((21/4)*(3/3))=(88/12)-(63/12)= 25/12....

2)(6*(5/7))-(5*(2/3))=((6*7+5)/7)-((5*3+2)/3)=(47/7)-(17/3)=((47/7)*(3/3))-((17/3)*(7/7))=      (141/21)-(119/21)= 22/21..... 

3)(12*(5/6))-(9*(3/8))=((12*6+5)/6)-((9*8+3)/8)=(77/6)-(75/8)=((77/6)*(4/4))-((75/8)*(3/3))=   (308/24)-(225/24)= 83/24.... 

4)(11*(7/15))-(6*(2/3))=((11*15+7)/15)-((6*3+2)/3)=(172/15)-(20/3)=(172/15)-((20/3)*(5/5))=(172/15)-(100/15) = 72/15....

5)(8*(1/5))-(3*(2/7))=((8*5+1)/5)-((3*7+2)/7)=(41/5)-(23/7)=((41/5)*(7/7))-((23/7)*(5/5))=    (287/35)-(115/35)= 172/35...

6)(5*(6/13))-(2*(2/3))=((5*13+6)/13)-((2*3+2)/3)=(71/13)-(8/3)=((71/13)*(3/3))-((8/3)*(13/13))=(213/39)-(104/39)= 109/39...

7)(9*(3/10))-(4*(3/5))=((9*10+3)/10)-((4*5+3)/5)=(93/10)-(23/5)=(93/10)-((23/5)*(2/2))=      (93/10)-(46/10)= 47/10...

8)(2*(3/14))-(1*(1/7))=((2*14+3)/14)-((1*7+1)/7)=(31/14)-(8/7)=(31/14)-((8/7)*(2/2))=          (31/14)-(16/14)= 15/14...

(12m + 27) + 5 · (31 - 17m) = 448

12m + 27 + 155 - 85m = 448

12m - 85m = 448 - 27 - 155

- 73m = 266

m = 266 : (-73)

m = - 266/73

<h3>m = - 3 целых 47/73</h3>

+7 +2 +4 +6 +1 +5 +8 +3 +10 +9

1.4×1.5÷2.1=1
9÷0.12÷300=0.25
0.36÷(4.5÷0.25)=0.02
5.6÷(120×0.7)=не получается

28100 м = 28 км 100 м
116*4 = 464 км - 28 км 100 м = 435 км 900 метров