（1）4.32-2.5+1.89=1.82+1.89=3.71；（2）13.58-（4.56+3.58）=13.58-3.58-4.56=10-4.56=5.44；（3）4.5×0.7+5.5×0.7=（4.5+5.5）×0.7=10×0.7=7；（4）82.4-12.4×5=82.4-62=20.4．
