tong cua hai so la 5,79 . tim hai so do , biet rang 9 lan so thu nhat cong 5 lan so thu hai duoc 33,87
Tong hai so bang 5,79.Tim hai so do,biet rang 5 lan so thu nhat cong voi so thu hai thi bang 10,71
tong cua 2 so bang 7,9 tim hai sso do biet rang 3 lan so hang thu nhat cong voi so hang thu hai thi duoc 13,3
tong 2 so la 5,07 . tim 2 so do biet rang 5 lan so thu nhat cong voi 3 lan so thu 2 duoc 19,27
tong hai so bang 6,8 tim hai so do bietrang 2 lan so thu nhat cong voi 5 lan so thu hai thi duoc 20,5
tong 2 so bng 10,45 tim 2 so do biet rang neu so hang thu nhat cong voi 4 lan so hang thu 2 thi duoc 22,45
Mot so co hai chu so bang 3 lan tong cac chu so cua no cong voi 7.Neu viet so do theo thu tu nguoc lai thi duoc so moi bang 7 lan tong cac chu so cua no cong voi 3.Tim so da cho
tong cua 2 so bang 43,75 tim 2 so do biet rang neu so thu 1 gap 5 lan va giu nguyen so thu 2 thi duoc tong moi bang 124,95
1 .trung binh cong cua hai phan so la 5/12 .neu tang phan so thu nhat gap 2 lan thi trung binh cong cua chung bang 2/3 .tim hai phan so do .
2.trung binh cong cua ba phan so la 13 /36 .neu tang phan so thu nhat gap 2 lan thi trung binh cong cua chung bang 19/36 ,cho biet phan so thu hai lon hon phan so thu ba 1 /12. tim ba phan so do .