tong cua hai so bang 5,07 tim hai so do biet rang 5 lan so thu nhat cong voi ba lan so thu hai thi duoc 19,27 ; bai 2 mot nguoi bo ra 1200000 dong mua hang hoa sau khi ban het so hang do thi duoc lai 15% tien von tinh so tien thu duoc khi ban het so hang do giai bai toan bang 2 cach ; bai 3 tinh dien tich cua hinh tam giac biet do dai day 6dm chieu cao 35 cm do dai day 5m 2cm chieu cao 43 dm ; bai 4 mot thua ruong hinh thang co day lon 200m day be bang 4/5 day lon va hon chieu cao la 10m trung binh cu 100m2 thu hoach duoc 60 kg thoc hoi tren thua ruong do nguoi ta thu hoach duoc bao nhieu ta thoc ; bai 5 duong kinh cua banh xe dap la 65cm hoi nguoi di xe dap di duoc bao nhieu met neu banh xe lan tren mat dat duoc 100 vong 1000 vong ; bai 6 : 18,06x 4 :42 +58: 25, b 2,34 : [ 2,34- 1,09] x 3,5 - 2,006