Tính tổng :
a) (-24) + 6 + 10 + 24 b) 15 +23+( -25) +(-23)
c) (-3) + ( -350 ) + (-7) + 350 d) ( -9 ) + ( -11 ) + 21 + ( -1)
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 )= 21 – (9+11+1) = 21 - 21 =0