问题 解答题

能简算的要简算.

(1)4-0.8÷4-0.8

(2)19.98×37-199.8×1.9+1998×0.82

(3)9.75+99.75+999.75+9999.75

(4)9999×7+1111×37.

答案

(1)4-0.8÷4-0.8,

=4-(0.2+0.8),

=4-1,

=3;

(2)19.98×37-199.8×1.9+1998×0.82

=19.98×37-19.98×19+19.98×82,

=(37+82-19)×19.98,

=100×19.98,

=1998;

(3)9.75+99.75+999.75+9999.75

=(10-0.25)+(100-0.25)+(1000-0.25)+(10000-0.25)

=10-0.25+100-0.25+1000-0.25+2000-0.25

=(10+100+1000+10000)-0.25×4

=11110-1,

=11109;

(4)9999×7+1111×37

=1111×9×7+1111×37,

=(9×7+37)×1111,

=(63+37)×1111,

=100×1111,

=111100.

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