goi so can tim la ab (a khac 0, a,b >10)
so mới là: 12ab
ta có: ab*26=12ab
ab*26=1200+ab
ab*26-ab=1200
ab*(26-1)=1200
ab*25=1200
ab=48
vay so can tim la 48
tim 1 so tu nhien co 3 chu so biet rang khi viet them chu so 9 vao ben trai so do ta duoc 1 so gap 26 lan so can tim
tim so tu nhien co 2 chu so ,biet rang neu viet them chu so 0 xen giua chu so hang chuc va hang don vi cua so do ta duoc so moi gap 10 lan so can tim .Neu viet them chu so 1 vao ben trai so vua nhan duoc thi so do gap len 3 lan.
Tìm so co hai chu so biet rang neu ta viet them chu so 2 vao ben trai va ben phai so do ta duoc so moi gap 36 lan so phai tim.
tim so tu nhien co 2 chu so neu viet them chu so 0 xen giua chu so hang chuc va hang don vi cua so do ta duoc so moi gap 10 lan so can tim . neu viet them chu so 1 vao ben trai so vua nhan duoc thi so do gap len 3 lan . so can tim
tim 1 so co 4 chu so , biet rang neu them chu so 1 vao ben trai so do ta duoc so moi gap 6 lan so phai tim . luy y bai giai
tim so co 3 chu so,biet rang khi viet them chu so 1 vao ben trai so do thi duoc so co 4 chu so gap 9 lan so phai tim
tim 1 so tu nhien biet rang neu them chu so 3 vao ben trai so do ta duoc 1 so gap 13 lan so da cho (so da cho la so co 2 chu so)
tim so co 2 chu so biet rang neu them chu so 0 xen giua chu so hang chuc va hang don vi cua so ta duoc lon gap 10 lan so da cho neu them chu so 1 vao ben trai so vua nhan duoc thi so do tang lon hon 3 lan
tim so co 2 chu so biet rang neu viet them vao truoc va sau so do 1 chu so 1 ta duoc 1so co 4 chu so gap 23 lan so phai tim
