bai 1 :mot lop hoc co 24 nam va 18 nu.duoc chia deu vao cac to,sao cho so nam trong cac to bang nhau va so nu trong cac to bang nhau?hoi co the chia duoc nhieu nhat bao nhieu to ? khi ay moi to co may nam?may nu? bai2:so doi vien thieu nien cua 1 truong thcs la 1 so lon hon 200 va nho hon 250.khi xep hang 4,hang 5,hang 8 deu vua du ko thua hoc sinh nao. tinh so hoc sinh khoi 8 cua truong do?
dien cac so 0;-1;1;2;-3;3;4;-4 vao cac o vuong o hinh ben[ moi o 1 so] sao cho tong cua ba so tren hang ngang , hang doc, duong cheo deu bang 0
Cho tap hop A={1;2;3;4;5;6;7;8;9} . Viet cac tap hop con cua tap hop A sao cho moi tap hop deu co 3 phan tu ma tong cac so trong moi tap hop deu bang 15
1.tim 2 so tu nhien co hieu bang 2002 va tich bang 2006.
2.cho 100 so tu nhien 1,2,3,4,....100.
co the chon duoc 71 so tu nhien sao cho tong cua chung bang tong cua 29 so con lai khong
3.mot so chan co 4 chu so , trong do so tao boi chu so hang tram va hang chuc gap 3 lan chu so hang nghin va gap 2 lan chu so hang don vi .
[CAC BAN GHI LOI GIAI GIUP MINH NHE MINH CAM ON]
Do : Hay dien cac so 1,-1,2,-2,3,-3vao cac o trong o hinh vuong ben (moi so vao 1 o) sao cho tong 3 so tren moi dong moi cot hoac moi duong cheo deu bang nhau
giup minh voi
Do: hay dien cac so 1,-1,2,-2,3,-3 vao cac o trong hinh vuong ben duoi ( moi so vao mot o) sao cho tng 3 s tren moi dong , moi cot co tong hoac moi duong cheo deu bang nhau (SGK trang 99) tap 1 lop 6
Cho 18 so nguyen sao cho tong cua 6 so bat ki trong cac so do deu la so am. Giai thich vi sao tong cua 18 so do lai la 1 so am? Bai toan co dung hay ko neu thay 18 so bang 19 so?
Bai 1 :Tim so tu nhien co 6 chu so biet chu so hang don vi la 4 va neu chuyen chu so do len hang dau tien thi so do tang gap 4 lan.
Bai 2:Cho 3 chu so a,b,c sao cho 0<a<b<c.
a]Viet tap hop cac so tu nhien co 3 chu so gom ca 3 chu so a,b,c.
b]Biet tong 2 so nho nhat trong tap A=488.Tim 3 chu so A,B,C.
cho mot so co ba chu so biet rang tong cac chu so hang tram va hang don vi bang chu so hang chuc. CMR so do chia het cho 11
