Bỏ dấu ngoặc rồi tính :
\(\eqalign{ & a)\;\left( {4 + 32 + 6} \right) + \left( {10 - 36 - 6} \right) \cr & b)\;\left( {77 + 22 - 65} \right) - \left( {67 + 12 - 75} \right) \cr & c) - \left( { - 21 + 43 + 7} \right) - \left( {11 - 53 - 17} \right). \cr} \)
\(\eqalign{ & a)\left( {4 + 32 + 6} \right) + \left( {10 - 36 - 6} \right) \cr&= 4 + 32 + 6 + 10 - 36 - 6 \cr & = (4 + 32 - 36) + 10 + (6 - 6) \cr&= (36 - 36) + 10 + 0 \cr&= 0 + 19 = 10 \cr & b)\left( {77 + 22 - 65} \right) - \left( {67 + 12 - 75} \right) \cr&= 77 + 22 - 65 - 67 - 12 + 75 \cr & = (77 - 67) + (22 - 12) + (75 - 65) \cr&= 10 + 10 + 10 = 30 \cr & c) - \left( { - 21 + 43 + 7} \right) - \left( {11 - 53 - 17} \right) \cr&= 21 - 43 - 7 - 11 + 53 + 17 \cr & = (21 - 11) + (53 - 43) + (17 - 7) \cr&= 10 + 10 + 10 = 30 \cr} \)