tim so chinh phuong n co ba chu so biet rang n chia het cho 5 va neu nhan n voi 2 thi tong cac chu so cua no khong doi

Tim so chinh phuong n co ba chu so, biet rang n chia het cho 5 va neu nhan n voi  2 thi tong cac chu so cua no khong thay doi

cho  cac so tu nhien n va 2n co tong cac chu so bang nhau 

a) chung minh n chia het cho 9

b)tim so chinh phuong n co 3 chu so biet n chia het cho5 va 2n thi tong cac chu so khong doi

• tim so chinh phuong n co 3chu so biet n chia het cho 3, n va 2n co tong cac chu so k doi

cho 1 so chinh phuong co 4 chu so. Biet rang chu so tan cung cua no la so nguyen to, tong cac chu so cua no cung la so chinh phuong va can bac 2 cua no co tong cac chu so cung la so chinh phuong

tim so co 2 chu so biet rang neu lay tong cac chu so cong voi tich cac chu so cua so do thi bang chinh no.

tim mot so tu nhienco hai chu so,biet rang khi chia no cho tong cac chu socua no thi duocthuong la 3 du 7 va neu doi hai chu so cua no cho nhau va cung chia cho tong hai chu so cua no thi duoc 7 du 3

tim so co ba chu so biet rang neu doi chu so hang tram va don vi cua no cho nhau thi gia tri cua no khong thay doi con chu so hang chuc bang mot phan ba tong hai chu so kia