So sánh hai phân số: \(\frac{-7}{31}va\frac{6}{31}\);\(\frac{-97}{128}va\frac{-99}{128}\) ;\(\frac{3}{7}va\frac{-6}{7}\);\(\frac{2}{5}va\frac{4}{5}\)\(\frac{-2}{5}va\frac{13}{5}\)\(\frac{4}{9}va\frac{7}{9}\)\(\frac{5}{12}va\frac{7}{12}\)\(\frac{-7}{15}va\frac{-8}{15}\)\(\frac{-2}{5}va\frac{4}{5}\)\(\frac{4}{7}va\frac{3}{7}\)\(\frac{-11}{13}va\frac{-15}{13}\)\(\frac{-2}{7}va\frac{-4}{14}\)\(\frac{_{-5}}{7}va\frac{-10}{7}\)\(\frac{-13}{5}va\frac{1}{5}\)\(\frac{-6}{7}va\frac{-3}{7}\)\(\frac{3}{7}va\frac{5}{7}\)\(\frac{-7}{9}va\frac{-5}{9}\)\(\frac{-3}{7}va\frac{-5}{7}\)\(\frac{-13}{9}va\frac{1}{9}\) so sánh số cùng mẫu số \(\frac{-7}{13};\frac{-4}{13}\) \(\frac{1}{7};\frac{-4}{-7}\)

1 a, 3 va 1/5  -  2 va  1/6    +   1/5

b, 5 va 12/13  -    2 va 15/26 + 1/26

c, 7 va 1/12 + 1/12 - 6 va 1/4

 2 tinh gia tri bieu thuc 

a, 3 va 2/9 - [1 va 5/8 + 1 va 2/9 ] - 3/8

b, 4 va 2/5 - 1 va 3/7 - 1 va 4/7 + 1/5

c, 1 va 9/12 - 5/4 - 1/2

3 tinh 

a, 6 nhan 7 nhan 8 nhan 9 nhan 1 tren 18 nhan 16 nhan 14 nhan 12 nhan 2

b, 4 nhan 15 nhan 9 nhan 24 tren 3 nhan 12 nhan 8 nhan 5 

4 rut gon cac phan so 

a, 96/150 ; 255/408 ; 630/224

b, 1515/1717; 352352/470470; 200620062006/200520052005

5 so sanh cac phan so 

a, 7/9 va 9/7 ; b, 135/120 va 13/8; c, 3535/4848 va 5/8 ; d, 650650/480480 va 222222/144144 

6, so sanh hai phan so 

a, 2005/2006 va 2006/2007 ; b, 2008/2007  va 2007/2006

cac ban lam tung buoc nha