31: (-29)+8-9
\(=\left(-29\right)+\left(8-9\right)\)
\(=-29-1=-30\)
32: \(\left(-14\right)-6-10\)
\(=\left(-14-6\right)-10\)
=-20-10
=-30
33: \(\left(-42\right)+10+2\)
\(=\left(-42\right)+\left(10+2\right)\)
=-42+12
=-30
34: \(\left(-45\right)+25-20\)
\(=\left(-45\right)+\left(25-20\right)\)
=-45+5
=-40
35: \(\left(-60\right)+17+3\)
\(=\left(-60\right)+\left(17+3\right)\)
=-60+20
=-40
36: \(\left(-48\right)+18-10\)
\(=\left(-48+18\right)-10\)
=-30-10
=-40