C = 1 - 2 - 3 + 4 + 5 - 6 - 7 + 8 + ... + 2017 - 2018 - 2019 + 2020
= (1 + 4 + 5 + 8 + ... + 2017 + 2020) - (2 + 3 + 6 + 7 + ... + 2018 + 2019)
= [(1 + 4) + (5 + 8) + ... + (2017 + 2020)] - [(2 + 3) + (6 + 7) + ... + (2018 + 2019)]
= (5 + 13 + ... + 4037) - (5 + 13 + ... + 4037)
= 0
=(1-2-3-4)+(5-6-7+8)+...+ (2017-2018-2019+2020)
=0+0+..+0
=0
a) 5+3.(-7)+4:(-2)
b)1-2-3+4+5-6-7+8.....+2017-2018-2019+2020+2021
1-2-3+4+5×6-7+8+...+2017-2018-2019+2020
Tính
A = 1 - 2 + 3 - 4 + 5 - 6 + 7 - 8 + 9 - ........... + 2019
B = 1 + 2 - 3 + 4 - 5 + 6 - 7 + .............. + 2017 + 2018 - 2019 + 2020
Tính S = 1 - 2 - 3 + 4 + 5 - 6 - 7 + 8 +...+ 2016 + 2017 - 2018 - 2019 + 2020
Tính hợp lí:
a. A= -1 + 3 - 5 + 7 - 9 +....- 2017 + 2019
b. B= 2 - 4 + 6 - 8 +...+ 2018 - 2020
c. C= 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8+...-111 - 112 + 113 + 114 + 115
tính giá trị của tổng
D=1-2-3+4+5-6-7+8+....+2017-2018-2019+2020
C=1001 - 1003 + 1005 - 1007+...+ 2013 - 2015+2017
2+3-4+5+6-7+8+9-10+...+2015+2016-2017+2018+2019-2020+2021+2022
Bài 1: Tính nhanh
A = 1 - 3 + 5 - 7+...- 2019 + 2021 - 2023
B = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 +...+ 2017 + 2018 + - 2019 - 2020
Help me :v
S3=1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2017+(-2018)+(-2019)+2020
Giúp mik vs, tối nay mik nộp rùi
