Question

Answer 1

a) 

\(126+\left(-10\right)+\left(-100\right)+\left(-126\right)=\left[126+\left(-126\right)\right]-\left(10+100\right)\\ =0-110\\ =-110\)

b) 

\(\left(-213\right)+89+13+11\\ =\left[-213+13\right]+\left(89+11\right)\\ =-200+100\\ =-100\)

Answer 2

a)

\(=\left[126+\left(-126\right)\right]+\left[\left(-10\right)+\left(-100\right)\right]=0+\left(-110\right)=-110\)

b)

\(=\left[\left(-213\right)+13\right]+\left(89+11\right)=-200+100=-100\)

Answer 3

\(a,126+\left(-10\right)+\left(-100\right)+\left(-126\right)\)
\(=\left[\left(126+\left(-126\right)\right)\right]+\left[\left(-10\right)+\left(-100\right)\right]\)
\(=0+\left(-110\right)\)
\(=-110\)

\(b,\left(-213\right)+89+13+11\)
\(=\left[\left(-213\right)+13\right]+\left(89+11\right)\)
\(=-200+100\)
\(=-100\)