voi 8 chu so 8 . hay lap cac so sao cho tong cac so do bang 1000
Tim cac so tu nhien sao cho tong cua so do voi cac chu so cua no bang 2009
voi 20 chu so 5 va cac dau cong em hay lap 1 tong co ket qua=1000
1.Cho 5 chu so 3,4,6,8,9.Lap duoc bn so co 4 chu so khac nhau tu cac chu so tren ? Tinh tong cac so do
giup minh voi
toan tren mang:cho a,b,c la 3 chu so khac nhau va khac0,co tong bang 4.Hay tim tong cua tat ca cac so 3 chu so khac nhau lap tu 3 chu so do.
cho cac chu so 2,3,5.hay lap tat ca cac so co 3chu so khac nhau va tinh tong cac so do
2 4 6 8 la cac so chan vay thi 1 3 5 7 9 la cac so le khi cong tung so lai ta se duoc 45 so chan la 20 so le la 25 khi chia tong cua cac chu so le
cho tong cua cac chu so chan ta duoc bao nhieu (khong du) de sao cho so do bang tong cua cac chu so le va chu so chan
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
Ta gọi số đó là ab
Ta có :
ab = ( a + b ) x 3 + 7 ( 1 )
a x 10 + b = a x 3 + b x 3 + 7
a x 7 = b x 2 + 7
7 x a - 7 = b x 2
ba = ( b + a ) x 7 + 3 ( 2 )
b x 10 + a = b x 7 + a x 7 + 3
b x 3 = a x 6 + 3
b x 1 = a x 2 + 1
Từ 1 ta viết 2 thành :
b x 2 = a x 4 + 2
= > a x 4 + 2 = 7 x a - 7
= > 7 x a - 4 x a = 9
3 x a = 9
=> a = 3 , b = 7
Số đó là 37
cho 4 chu so 0;2;4;6 . Hay lap tat ca cac so thap phan ma moi so co du 4 chu so da cho roi tinh tong cac so do
hay chia cac tren mat dong ho lam 2 nhom nhom 1 gom cac so tu nhie lien tiep va nhom 2 gom cac so con lai sao cho :
a) tong cac so cua nhom 1 bang tong cac chu so cua nhom 2
b) tong cac chu so cua nhom 1 bang tong cac chu so cua nhom 2
c) tong cac chu so cua nhom 1 bang 1 nua tong cac chu so cua nhom 2