（1）原式=-12-5-14+39=-31+39=8；（2）原式= 2 3 ×48- 3 8 ×48+ 5 24 ×48=32-18+10=24；（3）原式=-18× 4 9 × 4 9 ×（? 1 16 ）= 1 18 ；（4）原式=-63× 1 62 -49=-6-49=-55．
