Tính giá trị biểu thức: C = 1 + 2 - 3 - 4 + 5 + 6 - 7 - ... + 2014 - 2015 - 2016 + 2017 + 2018.
2 câu trả lời
C = $1$ + $2$ - $3$ -$ 4$ + $5 $+ $6$ - $7$ - ... + $2014$ - $2015$ - $2016$ + $2017$ + $2018$.
= $1$ + ($2$ - $3$ - $4$ + $5$) + ($6$ -$7$-$8$+$9$) + ... + ( $2014$ - $2015$ - $2016$ + $2017$) +$2018$
= $1$ + $0$ +$0$ +....+$0$+$2018$
= $1$+$2018$
= $2019$
C = `1 + 2 - 3 - 4 + 5 + 6 - 7 - ... + 2014 - 2015 - 2016 + 2017 + 2018.`
=`1 + (2-3-4+5)+ (6-7-8+9)+.........(2014-2015-2016+2017)+2018`
= `1+0+0+...2018`
= `1+2018`
=`2019`