sau khi phat minh ra ban co , nha phat minh đuoc vua cho phep tu chon phan thuong cho minh.ong ta von la mot nguoi thong minh ben xin vua : o thu nhat cho1hat thoc ,o thu hai la 2hat thoc ,o thu 3xin 4 hat ,va cu tu tu so hat thoc gap đoi so hat o ô truoc.nha vua khong biet toan hoc nen cho đo la phan thuong re mat va nhanh chong dong y,lenh cho nguoi giu kho dem va mang thoc cho nha phat minh .Tuy nhien ,khi nguoi giu kho sau hon mot tuan tinh toan tong so thoc cho nha vua thay khong co cach nao co the ban cho nha phat minh phan thuong đo. voi cach cua nha vua nhu vay thi o cuoi cúngo hat thoc se duoc viet thoc se viet duoi dang luy thua nhu the nao .

bai 1 : Tim hieu cua hai so, biet rang so lon them 735 don vi va so ben them 449 don vi thi duoc hieu moi la 2000.

Bai 2 : Khi thuc hien phep tru hai so, mot ban da so y viet sai nhu sau : o so bi tru co hai chu socuoi cung la 35 da viet thanh 53 nen phep tru sai co ket qua la 1234. Tim hieu dung cu ahia so do.

Bai 3 : TIm mot so biet rang so do cong voi so lon nhat co ba chu so khac nhau roi cong tiep voi so be nhat co bon chu so khac nhau thi duoc so be nhat co nam chu so.

Bai 4 ; Cho ba chu so tu nhieu A ; B ; C. Biet rang tong cua A va B la 492 ; tongg cua B va C la 936 ; tong cua C va A la 714. Tim ba so do.

Bai 5 : HAi kho chu atat ca 2500 tan thoc. Sau khi lay ra o moi kho so tan thoc nhu sau. thi kho thu nhat con 800 tan va kho thu hai con 500 tan. Hoi luc dau moi kho chua bao nhieu tan thoc?

A rat muon lam quen voi nu sinh no,ben nghi ra cach moi co ta toi an o nha hang.Nhung moi bang loi moi nhu thong thuong se de bi tu choi,the la A nghi ra 1 ke,roi noi voi nu sinh do:

  -Toi co 2 van de muon hoi co,rat mong co chi tra loi cho la"co" hoac "khong",khong tra loi bang cau khac,dong thoi 2 cau tra loi cua co lai can hoan toan hop li ve mat logich,tuc la khong mau thuan voi nhau.

  Nu sinh do nghe the thi bat cuoi,ben gat dau to y dong y nhu the.

  Ban co biet,A da hoi the nao de dat duoc muc dich moi duoc nu sinh do di an com voi minh khong?