\(a)\,\left( { - 24} \right) + 6 + 10 + 24\)
\(=\left[ {\left( { - 24} \right) + 24} \right] + \left( {6 + 10} \right) \)
\(= 0 + 16 = 16\)
\(b)\, 15 +23+( -25) +(-23)\)
\(=\left[ {15 + \left( { - 25} \right)} \right] + \left[ {23 + \left( { - 23} \right)} \right] \)\(= \left( { - 10} \right) + 0 = - 10\)
\(c)\, (-3) + ( -350 ) + (-7) +350\)
\(=\left[ {\left( { - 3} \right) + \left( { - 7} \right)} \right] + \left[ {\left( { - 350} \right) + 350} \right] \)\(= \left( { - 10} \right) + 0 = - 10\)
\(d)\, ( -9 ) + ( -11 ) +21 + ( -1 )\) \(= [(-9)+(-11)]+[21+(-1)]\) \(=(-20)+20\) \(=0\)
