求这道题的简便算法。
2个回答
展开全部
怎样简便就怎样算.
解:(1)356-298
=356-300+2
=56+2
=58;
(2)125×88
=125×8×11
=1000×11
=11000;
(3)102×99
=(100+2)×99
=100×99+2×99
=9900+198
=10098;
(4)987-(287+135)
=987-287-135
=700-135
=565;
(5)382×101-382
=382×(101-1)
=382×100
=38200;
(6)155+264+36+44
=(155+44)+(264+36)
=199+300
=499;
(7)58×29-29×48
=(58-48)×29
=10×29
=290;
(8)149×69-149+149×32
=149×(69-1+32)
=149×100
=14900;
(9)487-139-61-287
=(487-287)-(139+61)
=200-200
=0;
(10)99×99+99
=99×(99+1)
=99×100
=9900;
(11)125×25×32
=125×25×(8×4)
=(125×8)×(25×4)
=1000×100
=100000;
(12)125×(80-8)
=125×80-125×8
=10000-1000
=9000;
(13)346-69+54-31
=(346+54)-(69+31)
=400-100
=300.
解:(1)356-298
=356-300+2
=56+2
=58;
(2)125×88
=125×8×11
=1000×11
=11000;
(3)102×99
=(100+2)×99
=100×99+2×99
=9900+198
=10098;
(4)987-(287+135)
=987-287-135
=700-135
=565;
(5)382×101-382
=382×(101-1)
=382×100
=38200;
(6)155+264+36+44
=(155+44)+(264+36)
=199+300
=499;
(7)58×29-29×48
=(58-48)×29
=10×29
=290;
(8)149×69-149+149×32
=149×(69-1+32)
=149×100
=14900;
(9)487-139-61-287
=(487-287)-(139+61)
=200-200
=0;
(10)99×99+99
=99×(99+1)
=99×100
=9900;
(11)125×25×32
=125×25×(8×4)
=(125×8)×(25×4)
=1000×100
=100000;
(12)125×(80-8)
=125×80-125×8
=10000-1000
=9000;
(13)346-69+54-31
=(346+54)-(69+31)
=400-100
=300.
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