Bai 1
3 nguoi cung lam mot cong viec,neu lam rieng nguoi thu nhat mat 4 gio,nguoi thu hai mat 5 gio, nguoi thu ba mat 6 gio.Hoi neu lam chung mat bao nhieu gio?
Bai2
tinh tong cac phan so lon hon -1/14 va nho hon -1/15 va co tu la -4.
Bai3:Tinh tong
-24/72 + -20/48
5/4 + -1/2 + -7/8
3+-7/9+5/6
-6/7+-4/5+(-4)
15/-60+-42/56