A = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... + 2018 – 2019 - 2020 + 2021
A = (1 + 2 - 3 - 4) + ... + (2017 + 2018 – 2019 - 2020) + 2021
A = (-4) + ... + (-4) + 2021 +
2020 : 4 = 505
A = (-4) . 505 + 2021
A = (-2020) + 2021
A = 1
Vậy A=1
Mình gửi bạn nha !!!!!
S = 1+2-3-4+5+6-7-8+9+10+ ..... + 2018-2019-2020+2021-2022+2023
2+3-4+5+6-7+8+9-10+...+2015+2016-2017+2018+2019-2020+2021+2022
1-2-3+4+5-6-7+8+...+2018-2019-2020+2021+2022-2023
Tính hợp lí (nếu có thể):
A= -1-2+3+4-5-6+7+8-9-10+...+2019+2020-2021-2022+2023
Tính S= 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - ... + 2018 - 2019 - 2020 + 2021
Tính S= 1+2-3-4+5+6-7-8+9+10- .......+2018-2019-2020+2021
Tính: S = 1+2-3-4+5+6-7-8+9+10+ ..... + 2018-2019-2020+2021
tính s = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 -... + 2018 - 2019 - 2020 + 2021
tính s = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 -... + 2018 - 2019 - 2020+2021
