\(a,\left(-5\right)+11+\left(-15\right)+21+\left(-25\right)+31+...+\left(-95\right)+101\\ =\left[\left(-5\right)+11\right]+\left[\left(-15\right)+21\right]+\left[\left(-25\right)+31\right]+...+\left[\left(-95\right)+101\right]\\ =6+6+6+...+6\left(10\text{ số }6\right)\\ =6\cdot10\\ =60\)
\(b,3+\left(-12\right)+13+\left(-22\right)+23+\left(-32\right)+...+93+\left(-102\right)\\ =\left[3+\left(-12\right)\right]+\left[13+\left(-22\right)\right]+\left[23+\left(-32\right)\right]+...+\left[93+\left(-102\right)\right]\\ =\left(-9\right)+\left(-9\right)+\left(-9\right)+...+\left(-9\right)\left(10\text{ số }-9\right)\\ =\left(-9\right)\cdot10\\ =-90\)
\(a,\left(-5\right)+11+\left(-15\right)+21+\left(-25\right)+31+...+\left(-95\right)+101\)
\(=\left[\left(-5\right)+11\right]+\left[\left(-15\right)+21\right]+\left[\left(-25\right)+31\right]+...+\left[\left(-95\right)+101\right]\)
\(=6+6+6+...+6\) (10 số 6)
\(=6.10=60\)
\(\)
\(a)-5+11+(-15)+21+(-25)+31+.......+(-95)+101\)
\(=(-5+11)+(-15+21)+(-25+31)+.....+(-95+101)\)
\(=6+6+6+..........+6\)(10 số 6)
\(=6.10\)
\(=60\)
Vậy....
Câu b tương tự
a) \(-5+11+\left(-15\right)+21+\left(-25\right)+31+...+\left(-95\right)+101\)
\(=\left(-5+11\right)+\left(-15+21\right)+\left(-25+31\right)+...+\left(-95+101\right)\)
\(=6+6+6+...+6\) (10 số 6)
\(=6\cdot10\)
\(=60\)
b) \(3+\left(-12\right)+13+\left(-22\right)+23+\left(-32\right)+...+93+\left(-102\right)\)
\(=3-12+13-22+23-32+...+93-102\)
\(=\left(3-12\right)+\left(13-22\right)+\left(23-32\right)+...+\left(93-102\right)\)
\(=-9+\left(-9\right)+\left(-9\right)+...+\left(-9\right)\) (10 số -9)
\(=-9\cdot10\)
\(=-90\)
