28-(-3 5/12)+(-4 23/30-2 1/4)=

4,6-1 11/15-(-2,3+5 1/3)=

-1 2/3×3,4×(-2 2/17)=

1 9/31×(-3,1)×(-17,75)=

по действием,6 класс.

28-(-3 5/12)+(-4 23/30-2 1/4)=24,4

1) -4 23/30-2 1/4 = -4 46/60 - 2 15/60 = -7 1/60

2) 28-(-3 5/12)= 28 + 3 5/12 = 31 5/12

3) 31 5/12 + (-7 1/60) = 31 25/60 - 7 1/60 = 24 24/60 = 24 2/5

4,6-1 11/15-(-2,3+5 1/3)= -1/30

1) -2,3+5 1/3 = - 2 3/10 + 5 1/3 = -2 9/30 + 5 6/30 = 2 27/30 = 2 9/10

2)4,6-1 11/15 = 4 6/10 - 1 11/15 = 4 18/30 - 1 22/30 = 2 26/30

3) 2 26/30 - 2 9/10 = 2 26/30 - 2 27/30 = - 1/30

-1 2/3×3,4×(-2 2/17)=2 11/17

1)-1 2/3×3,4 = -5/3 • 3/4 = -5/4 = -1 1/4

2) -1 1/4×(-2 2/17)=-5/4 • (-36/17) = -5/1 • (-9/17) = 45/17 = 2 11/17

1 9/31×(-3,1)×(-17,75)=71

1) 1 9/31×(-3,1) = 40/31 • (-31/10) = -4

2) -4/1 • (-1775/100) = -1/1 • (-1775/25) = 1775/25 = 71