номер 4
1 2/3+5/6= 1 4/6+5/6=1 9/6=1 3/6=1 1/2
4/9 * 3/8= (4*3)/9*8)=12/72=1/6
номер 5
а) 6 1/3-8=-(8-6 1/3)=- 1 2/3
б) - 2 2/7+4 3/5=-( 4 3/5-2 2/7)= -( 4 21/35- 2 10/35)=-2 11/35
в) 5 1/3 - 6 1/4= -( 6 1/4- 5 1/3)=- ( 6 3/12 -5 4/12)= -( 5 15/12-5 4/12)=-11/12
г) 3/8 : (-9/16)=3/8 *(-16/9)=- (3*16)/(8*9)= -(1*2)/(1*3)=-2/3
д) 5/12*(-6)= -(5*6)/12=-(5*1)/2=-5/2=- 2 1/2
е) - 3 2/9 * 3=-( 3+2/9)*3=-(3*3+2/9*3)=-(9+6/9)=-(9+2/3)=- 9 2/3
номер 4
1 2/3+5/6= 1 4/6+5/6=1 9/6=1 3/6=1 1/2
4/9 * 3/8= (4*3)/9*8)=12/72=1/6
номер 5
а) 6 1/3-8=-(8-6 1/3)=- 1 2/3
б) - 2 2/7+4 3/5=-( 4 3/5-2 2/7)= -( 4 21/35- 2 10/35)=-2 11/35
в) 5 1/3 - 6 1/4= -( 6 1/4- 5 1/3)=- ( 6 3/12 -5 4/12)= -( 5 15/12-5 4/12)=-11/12
г) 3/8 : (-9/16)=3/8 *(-16/9)=- (3*16)/(8*9)= -(1*2)/(1*3)=-2/3
д) 5/12*(-6)= -(5*6)/12=-(5*1)/2=-5/2=- 2 1/2
е) - 3 2/9 * 3=-( 3+2/9)*3=-(3*3+2/9*3)=-(9+6/9)=-(9+2/3)=- 9 2/3