1so sanh phan so
12/25 va 25/49 80/95 va 144/153
6 tinh gia tri bieu thucphanso
1phan 72+1phan56+1 phan 42+ 1phan 30 +1phan 20 + 1phan 12
7tinh nhanh phan so
17 phan 12+ 9phan 7-(2phan7 -7phan 12)
11phan7 nhan (38 phan 45 nhan 17 phan 11 )
(1+1phan2 ) nhan (1+1phan3 ) nhan ....... nhan (1+1phan2005
9 cho phan so 25phan 42 tim so tu nhien a sao cho khi them vao tu so cua phan so da cho va giu nguyen mau so thi duoc phan so moi bang 6phan 7