1 + 2 + 8 + 9 + 1 + 2 + 8 + 9 + 10 + 10
= (1 + 9) + (1 + 9) + (2 + 8) + (2 + 8) + 10 + 10
= 10 + 10 + 10 + 10 + 10 + 10
= 60
=1+9+2+8+1+9+2+8+10+10
=10+10+10+10+10+10
=10x6
=60
k mk nha mk k lại!
1 + 2 + 8 + 9 + 1 + 2 + 8 + 9 + 10 + 10
= (1 + 9) + (2 + 8) + (1 + 9) + (2 + 8) + 10 + 10
= 10 + 10 + 10 + 10 + 10 + 10
= 10 x 6
= 60
1 + 2 + 8 + 9 + 1 + 2 + 8 + 9 + 10 + 10
= (1 + 9) + (1 + 9) + (2 + 8) + (2 + 8) + 10 + 10
= 10 + 10 + 10 + 10 + 10 + 10
= 60