Bài style="mso-bidi-font-weight: normal"> 15: style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;mso-font-width:182%;mso-no-proof:yes"> Có style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> bao nhiêu style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> tự style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> nhiên style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.1pt; mso-no-proof:yes"> có style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> 6 style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.1pt;mso-no-proof:yes"> chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> với: a) style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.4pt;mso-no-proof:yes"> Chữ style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.55pt; mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.35pt;mso-no-proof:yes"> và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> cuối style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:-.05pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> nhau? b) style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.4pt;mso-no-proof:yes"> Chữ style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.55pt; mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.35pt;mso-no-proof:yes"> và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> cuối style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> khác style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> nhau? c) Hai style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> chữ style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> nhau và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> hai chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> cuối style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:-.05pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé Tổ hợp
a) style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.4pt;mso-no-proof:yes"> Chữ style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.55pt; mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.35pt;mso-no-proof:yes"> và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> cuối style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:-.05pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> nhau? b) style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.4pt;mso-no-proof:yes"> Chữ style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.55pt; mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.35pt;mso-no-proof:yes"> và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> cuối style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> khác style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> nhau? c) Hai style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> chữ style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> nhau và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> hai chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> cuối style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:-.05pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé Tổ hợp
b) style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.4pt;mso-no-proof:yes"> Chữ style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.55pt; mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.35pt;mso-no-proof:yes"> và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> cuối style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> khác style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> nhau? c) Hai style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> chữ style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> nhau và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> hai chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> cuối style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:-.05pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé Tổ hợp
c) Hai style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:-.05pt; mso-no-proof:yes"> chữ style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.3pt;mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> đầu style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.55pt;mso-no-proof:yes"> nhau và style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.3pt;mso-no-proof:yes"> hai chữ style="font-size:12.0pt; mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family: Calibri;mso-bidi-font-family:Calibri;color:black;letter-spacing:.3pt; mso-no-proof:yes"> số style="font-size:12.0pt;mso-bidi-font-size: 11.0pt;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family: Calibri;color:black;letter-spacing:.55pt;mso-no-proof:yes"> cuối style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:-.05pt;mso-no-proof:yes"> giống style="font-size:12.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri; mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;color:black; letter-spacing:.35pt;mso-no-proof:yes"> nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé Tổ hợp
* chú ý giải chi tiết ở câu b,c hộ em nhé Tổ hợp
Bài 15: Có bao nhiêu số tự nhiên có 6 chữ số với: a) Chữ số đầu và chữ số cuối giống nhau? b) Chữ số đầu và cuối khác nhau? c) Hai chữ số đầu giống nhau và hai chữ số cuối giống nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé
a) Chữ số đầu và chữ số cuối giống nhau? b) Chữ số đầu và cuối khác nhau? c) Hai chữ số đầu giống nhau và hai chữ số cuối giống nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé
b) Chữ số đầu và cuối khác nhau? c) Hai chữ số đầu giống nhau và hai chữ số cuối giống nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé
c) Hai chữ số đầu giống nhau và hai chữ số cuối giống nhau?* chú ý giải chi tiết ở câu b,c hộ em nhé
* chú ý giải chi tiết ở câu b,c hộ em nhé