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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.

题目详情
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.
▼优质解答
答案和解析
(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.