递等式计算,能简便的用简便计算.(1)1.01×9.9;(2-查字典问答网
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  递等式计算,能简便的用简便计算.(1)1.01×9.9;(2)7.64×0.5-2.95;(3)1.25×32;(4)12.5×9.7-12.5×8.7;(5)0.25×3.2×12.5;(6)81.2×0.6×9.3.

  递等式计算,能简便的用简便计算.

  (1)1.01×9.9;

  (2)7.64×0.5-2.95;

  (3)1.25×32;

  (4)12.5×9.7-12.5×8.7;

  (5)0.25×3.2×12.5;

  (6)81.2×0.6×9.3.

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2020-04-1820:20
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潘雪增

  (1)1.01×9.9

  =1.01×(10-0.1)

  =1.01×10-1.01×0.1

  =10.1-0.101

  =9.999

  (2)7.64×0.5-2.95

  =3.82-2.95

  =0.87

  (3)1.25×32

  =1.25×8×4

  =10×4

  =40

  (4)12.5×9.7-12.5×8.7

  =12.5×(9.7-8.7)

  =12.5×1

  =12.5

  (5)0.25×3.2×12.5

  =0.25×4×0.8×12.5

  =(0.25×4)×(0.8×12.5)

  =1×10

  =10

  (6)81.2×0.6×9.3

  =48.72×9.3

  =453.096

2020-04-18 20:21:36
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