数学简便计算：0.25*0.64*4/0.64 9.9*8+7.7*4 9.9*22+3.3*34

0.25*0.64*4/0.64
=0.25*4*0.64/0.64
=1
9.9*8+7.7*4
=(10-0.1)*8+(8-0.3)*4
=80-0.8+32-1.2
=112-2
=110
9.9*22+3.3*34
=(10-0.1)*22+(3+0.3)*34
=220-2.2+102+10.2
=322+8
=330
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数学简便计算：
0.25*0.64*4/0.64
解,得：
==(0.25*4)0.64/0.64
==1

9.9*8+7.7*4
解,得：
==(10-0.1)*8+(8-0.3)*4
==80-0.8+32-1.2
==112-2
==110

9.9*22+3.3*34
解,得：
==(10-0.1)*22+(3+0.3)*34
==220-2.2+102+10.2
==322+8
==330