\(B=\left[1+\left(-3\right)\right]+\left[5+\left(-7\right)\right]+........+\left[97+\left(-99\right)\right]+101\)
\(=\left(-2\right)+\left(-2\right)+.......+\left(-2\right)+101\)( có 25 số -2)
\(=\left(-2\right).25+101\)
\(=\left(-50\right)+101\)
\(=51\)
\(B=1+\left(-3\right)+5+\left(-7\right)+...+97+\left(-99\right)+101\)
\(\Rightarrow B=\left[1+\left(-3\right)\right]+\left[5+\left(-7\right)\right]+...+\left[97+\left(-99\right)\right]+101\)
\(\Rightarrow B=\left(-2\right)+\left(-2\right)+...+\left(-2\right)+101\)
có 25 số -2
\(\Rightarrow B=\left(-2\right).25+101\)
\(\Rightarrow B=-50+101\)
\(\Rightarrow B=51\)
Trả lời:
\(B=1+\left(-3\right)+5+\left(-7\right)+...+97+\left(-99\right)+101\)(Có 51 số)
\(B=\left[1+\left(-3\right)\right]+\left[5+\left(-7\right)\right]+...+\left[97+\left(-99\right)\right]+101\)
\(B=\left(-2\right)+\left(-2\right)+...+\left(-2\right)+101\)( Có 25 số (-2) )
\(B=\left(-2\right)\times25+101\)
\(B=\left(-50\right)+101\)
\(B=51\)
Vậy\(B=51\)
Hok tốt!
Good girl
B=1-3+5-7+..+97-99+101
B=101-99+97-95+....+5-3+1
Cộng cả 2 lại sẽ đc: 2B=102-102+102-102+...+102-102+102=102
suy ra B=102/2+51
