脱式计算，能简算的要简算．27.9-13.06+2.14.7×11-4.728.8×6.3-6.3×18.84.8+2.4×985.37-（2.37-1.8）20.01-13.78+6.78．

Question

脱式计算，能简算的要简算． 27.9-13.06+2.1	4.7×11-4.7	28.8×6.3-6.3×18.8
4.8+2.4×98	5.37-（2.37-1.8）	20.01-13.78+6.78．

Answer 1

（1）27.9-13.06+2.1
=（27.9+2.1）-13.06
=30-13.06
=16.94

（2）4.7×11-4.7
=4.7×（11-1）
=4.7×10
=47

（3）28.8×6.3-6.3×18.8
=（28.8-18.8）×6.3
=10×6.3
=63

（4）4.8+2.4×98
=4.8+2.4×2×49
=4.8+4.8×49
=4.8×（1+49）
=4.8×50
=240

（5）5.37-（2.37-1.8）
=5.37-2.37+1.8
=3+1.8
=4.8

（6）20.01-13.78+6.78
=20.01-（13.78-6.78）
=20.01-7
=13.01