问题 解答题

用简便方法计算下列各题.

20×0.4+0.6×0.20

(12×5)×(0.2×24)

15×0.4+8×0.75.

答案

(1)20×0.4+0.6×0.20

=2×4+0.06×2

=(4+0.06)×2

=4.06×2

=8.12;

(2)(12×5)×(0.2×24)

=12×(5×0.2)×24

=12×1×24

=288;

(3)15×0.4+8×0.75

=6+6

=12.

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