cho 31 so nguyen trong do tong cua 5 so bat ki la mot so duong.chung minh rang tong cua 31 so do la duong
Cho 61 so nguyen .Hoi tong cua 61 so nguyen do la so nhu the nao neu :
a,Tong cua 6 so bat ki trong chung la mot so nguyen am
b, tong cua 6 so bat ki trong chung la mot so nguyen duong
Cho 31 so nguyen trong do co 5 so bat ki co tong la so nguyen duong.Hay chung to rang tong cua 31 so do deu la so nguyen duong
cho 25 so nguyen trong do tich cua 3 so nguyen bat ki la mot so nguyen duong chung minh rang tat ca 25 so nguyen da cho deu la so nguyen duong
Cho 21 so nguyen trong do tong cua 5 so bat ki la 1 so nguyen duong. CMR tong cua 21 so do la 1 so nguyen duong
Cho 2014 so nguyen, trong do tich cua 3 so bat ki luon la 1 so nguyen am.chung to rang tich cua 2014 so nguyen do la mot so nguyen duong
Ai nhanh minh tick luon
cho 31 so nguyen trong do tong cua 5 so bat ki la 1 so duong . chung minh rang tong cua 31 so do la so duong
cho 16 so nguyen trong do tich cua 3 o bat ky luon la mot so nguyen am. chung to rang tich cua 16 so nguyen do la mot so nguyen duong
minh can gap!
cho 25 so nguyen trong do tong cua 3 so bat ki la 1 so duong . chung minh rang tong cua 25
so do la so duong