99.99×55.55÷11.1119.9×19.8-19.7×19.6(1+4+7+…+2008+2011)-(2+5+8+…+2006+2009)0.1÷0.1÷0.1÷…÷0.120个0.1.-

题目简介

99.99×55.55÷11.1119.9×19.8-19.7×19.6(1+4+7+…+2008+2011)-(2+5+8+…+2006+2009)0.1÷0.1÷0.1÷…÷0.120个0.1.-

题目详情

99.99×55.55÷11.11
19.9×19.8-19.7×19.6
(1+4+7+…+2008+2011)-(2+5+8+…+2006+2009)
0.1÷0.1÷0.1÷…÷0.1
20个0.1
题型:解答题难度:中档来源:不详

答案

(1)99.99×55.55÷11.11,
=99.99×(55.55÷11.11),
=99.99×5,
=(100-0.01)×5,
=500-0.05,
=499.95;

(2)19.9×19.8-19.7×19.6,
=(20-0.1)×(20-0.2)-(20-0.3)×(20-0.4),
=400-4-2+0.02-(400-8-6+0.12),
=14-0.12-6+0.02,
=7.9;

(3)(1+4+7+…+2008+2011)-(2+5+8+…+2006+2009),
=(1+2011)×[(2011-1)÷3+1]-(2+2009)×[(2009-2)÷3+1],
=(2011+1)×671-2011×670,
=2011×671+671-2011×670,
=2011×(671-670)+671,
=2011+671,
=2682;

(4)
0.1÷0.1÷0.1÷…÷0.1
20个0.1

=1÷0.1÷…÷0.1(19个0.1),
=1×1018,
=1018.

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