`C=-1-2+3+4-5-6+7+8-9-10+11+12-..-2017-2017+2019+2020`
`C=(-1-2+3)+(4-5-6+7)+(8-9-10+11)+..+ (2016-2017-2018+2019)+2020`
`C=0+0+0+..+0+2020`
`C = 2020`
`C=-1-2+3+4-5-6+7+8-9-10+11+12-..-2017-2017+2019+2020`
`C=(-1-2+3)+(4-5-6+7)+(8-9-10+11)+..+ (2016-2017-2018+2019)+2020`
`C=0+0+0+..+0+2020`
`C = 2020`
1+2-3-4-5+6+7-8-9-10+11+12-13-14-15+...+2011+2012-2013-2014-2015+2016+2017-2018-2019-2020 giup mik v
2+3-4+5+6-7+8+9-10+...+2015+2016-2017+2018+2019-2020+2021+2022
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 hợp lý:
A= 21.\(10^2\)-11.100+90.\(10^2\)+\(2^2\).\(5^2\).125.16
B= \(\dfrac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)
C= 3+5-7-9+11+13 -13-17+19+...+2013-2015-2017+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
1+2-3-4+5+6-7-8+9+10-11-12...+2018-2019-2020+2021
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
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
C = 1-2-3+4+5-6-7+8+...+2017-2018-2019+2020