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32×78≈29×38≈112×34≈94×52≈87×213≈61×89≈304×37≈51×204≈632×97≈83×420≈42×125≈501×31≈128×91≈85×228≈49×89≈

题目详情
32×78≈ 29×38≈ 112×34≈ 94×52≈
87×213≈ 61×89≈ 304×37≈ 51×204≈
632×97≈ 83×420≈ 42×125≈ 501×31≈
128×91≈ 85×228≈ 49×89≈
▼优质解答
答案和解析
(1)32×78,
≈30×80,
=2400;
(2)29×38,
≈30×40,
=1200;
(3)112×34,
≈110×30,
=3300;
(4)94×52,
≈90×50,
=4500;
(5)87×213,
≈90×210,
=18900;
(6)61×89,
≈60×90,
=5400;
(7)304×37,
≈300×40,
=12000;
(8)51×204,
≈50×200,
=10000;
(9)632×97,
≈630×100,
=63000;
(10)83×420,
≈80×420,
=33600;
(11)42×125,
≈40×130,
=5200;
(12)501×31,
≈500×30,
=15000;
(13)128×91,
≈130×90,
=11700;
(14)85×228,
≈90×230,
=20700;
(15)49×89,
≈50×90,
=4500.
故答案为:2400,1200,3300,4500,18900,5400,12000,10000,63000,33600,5200,15000,11700,20700,4500.