=(4+1)+(4+1)+(4+1)+(4+1)+(2+3)+(2+3)+(2+3)+(2+3)
=5+5+5+5+5+5+5+5
=5x8
=40
1 +1 + 1 + 1 + 2 + 2 + 2 + 2 + 3 + 3 + 3 + 3 + 4 + 4 + 4 + 4 40
tk mk bn mk nhanh nhất mà
1 + 1 + 1 + 1 + 2 + 2 + 2 + 2 + 3 + 3 + 3 + 3 + 4 + 4 + 4 + 4
= ( 1 + 4 ) + ( 1 + 4 ) + ( 1 + 4 ) + ( 1 + 4 ) + ( 2 +3 ) + ( 2 +3 ) + ( 2 +3 ) + ( 2 +3 )
= 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 = 5 x 8
= 40
1+1+1+1+2+2+2+2+3+3+3+3+4+4+4+4
= 4+8+12+16
=12+12+16
=24+16
=40
h nhé
1 + 1 + 1 + 1 + 2 + 2 + 2 + 2 + 3 + 3 + 3 + 3 + 4 + 4 + 4 + 4
= 1 x 4 + 2 x 4 + 3 x 4 + 4 x 4
= 4 + 8 + 12 + 16
= 40
1 + 1 + 1 + 1 + 2 + 2 + 2 + 2 + 3 + 3 + 3 + 3 + 4 + 4 + 4 +4
= 1 x4 + 2 x 4 + 3x 4 + 4 x 4
= 4 + 8 + 12 + 16
= 40