Question

[DangHoangTuan]

Tinh nhanh:

1-2-3-4+5-6-7-8+9-10-11-12+...+97-98-99-100

Answer 1

[pham khac thai]

1 nhé bạn

Answer 2

[✰Ťøρ ²⁷ Ťɾїệʉ Vâɳ ŇD✰]

1-2-3-4+5-6-7-8+9-10-11-12+...+97-98-99-100

=(1-2-3-4)+(5-6-7-8-)+(9-10-11-12)+....+(97-98-99-100)

=(-8)+(-16)+(-24)+.....+(-200)

=(-8).(1+2+3+4+.....+25)

=(-8).325

=(-2600)