1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
=(1+9)+(2+8)+(3+7)+(4+6)+5+10
=10 + 10 + 10 + 10 + 5 + 10
=10 x 5 + 5
=50+5
=55
Ai kb không??
1 + 2 + 3 + 4 + 5 +6 +7 + 8 + 9 + 10 =55
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= 55
= ( 1 + 9) + ( 2 + 8) + ( 3 + 7 ) + ( 4 + 6 ) + 5 + 10
= 10 + 10 + 10 + 10 + 5 + 10
= 55
Ủng hộ mik nha
Co; 1 + 2+ 3 + 4 + 5 + 6 +7 + 8+ 9 +10
= (1+10) + (2+9) + (3+8) + (4+7) + (5+6)
= 11 + 11 + 11 + 11 +11
= 11 . 5
= 55
cau gui qua mk di mk het luot moi kb mat roi!!!
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= 3 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= 6 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= 10 + 5 + 6 + 7 + 8 + 9 + 10
= 15 + 6 + 7 + 8 + 9 + 10
= 21 + 7 + 8 + 9 + 10
= 28 + 8 + 9 + 10
= 36 + 9 + 10
= 45 + 10
= 55
1+2+3+5+6+7+8+9+10=(1+9)+(2+8)+(3+7)+(4+6)+10 +5=10+10+10+10+10+5=55