1 + 2 + 3 + 4 + 5 + 6
= ( 1 + 6 ) + ( 2 + 5 ) + ( 3 + 4 )
= 7 + 7 + 7
= 7 x 3
= 21
1+2+3+4+5+6
=(6+4)+(5+3+2)+1
=10+10+1
=20+1
=21
h mik nha
1 + 2 + 3 + 4 + 5 + 6
= 1 + 2 = 3 + 3 = 6 + 4 = 10 + 5 = 15 +6 = 21
Ket qua phep cong la:
1+2+3+4+5+6=21
Dap so: 21