Question

[Trần Thị Hảo]

Bài 1: Tính nhanh :

1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + .... - 299 - 300 + 301 + 302

Answer 1

[Phan Thanh Tịnh]

1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... - 299 - 300 + 301 + 302 = 1 + (2 - 3 - 4 + 5) + (6 - 7 - 8 + 9) + ... + (298 - 299 - 300 + 301) + 302

= 303

Answer 2

[o0o I am a studious person o0o]

\(1+2-3-4+5+6-......-299-300+301+302\)

\(=1+\left(2-3-4+5\right)+\left(6-7-8+9\right)+.....+\left(298-299-300+301\right)+302\)

\(=1+0+0+0+....+302\)

\(=303\)