8• 7/8= (сокращаем 8 и 8 на 8) = 1•7/1=7
3/8• 8/3= (сокращаем 3 и 3 на 3; 8 и 8 на 8) = 1/1• 1/1= 1
1: 3/8= 1• 8/3= 8/3= 2 2/3
1- 3/8= 8/8- 3/8= 5/8
1+ 3/8= 1 3/8
-5 +4 1/5=-(5-4 1/5)= -(4 5/5-4 1/5)= -4/5
5• 4 1/5= 5• (4•5+1)/5= 5• 21/5=
(Сокращаем 5 и 5 на 5) =1•21/1=21
5: 4 1/5= 5: (4•5+1)/5= 5: 21/5= 5•5/21= 25/21= 1 4/21
1 1/2: 1/4= (1•2+1)/2 • 4/1= 3/2• 4/1= (сокращаем 2 и 4 на 2) =3/1•2/1=6
1 1/2• 1/4= (1•2+1)/2• 1/4= 3/2•1/4= 3/8
2/5: 2/5= 2/5• 5/2= (сокращаем 2 и 2 на 2;, 5 и 5 на 5) = 1/1•1/1=1
2/5: 5/2= 2/5• 2/5= 4/25
1- 5/2= 1- 2 1/2= -(2 1/2- 1)= -1 1/2
3 6/7- 4/7= 3 2/7