Cho so chan co 4 chu so ma tong cac chu so cua no bang 24 . Neu viet so do theo thu tu nguoc lai thi van duoc so da cho . Hay tim so da cho , biet rang nhom 2 chu so ben trai lon hon nhom 2 chu so ben phai la 36 don vi .
tim so co ba chu so biet rang neu viet them chu so 1 vao ben phai so do thi ta duoc mot so gap 3 lan so co duoc bang cach viet them chu so 2 vao ben trai so do
cho so co 3 chu so co tong la 12chu so o giua bang 2 chu so ben cong lai neu viet theo thu tu nguoc lai thi so do tang 396.tim so da cho
tim mot so co ba chu so biet rang neu viet them chu so 5 vao ben trai so do thi ta duoc so moi ma tong cua so moi va so da cho bang 5472. so phai tim la......
khi viet them vao ben phai va ben trai so co 2 chu so moi ben 1 chu so 5 thi ta duoc so moi va tong cua so moi va so phai tim bang 5544 tim so da cho
cho so co 2 chu so neu ta viet them vao ben phai hoac ben trai chinh so do thi ta duoc so moi va tong cua so moi voi so da cho bang 2754 tim so da cho
tim mot so tu nhien co hai chu so biet neu viet them mot chu so 0 vao ben phai va mot chu so 1 vao ben trai so do thi ta duoc so moi bang 50 la so phai tim
tim so co 3 chu so biet rang khi viet them chu so 7 vao ben phai so do ta duoc so be hon khi viet them chu so 7 vao ben trai la 5778 don vi
tim hai so co 2 chu so biet rang tong cua hai so do la 98 neu gep so lon vao ben trai va ben phai cua so be deu duoc cac so co 4 chu so ma hieu cua chung bang 1386 tim hai so do