四、计算题:快急!不能直接写得数!1.100+99-98-97+96+95-94-93+...+8+7-6-5+4+3-2-12.0.2001×0.19981998-0.1998×0.20012001
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![四、计算题:快急!不能直接写得数!1.100+99-98-97+96+95-94-93+...+8+7-6-5+4+3-2-12.0.2001×0.19981998-0.1998×0.20012001](/uploads/image/z/6679745-17-5.jpg?t=%E5%9B%9B%E3%80%81%E8%AE%A1%E7%AE%97%E9%A2%98%EF%BC%9A%E5%BF%AB%E6%80%A5%21%E4%B8%8D%E8%83%BD%E7%9B%B4%E6%8E%A5%E5%86%99%E5%BE%97%E6%95%B0%211%EF%BC%8E100%EF%BC%8B99%EF%BC%8D98%EF%BC%8D97%EF%BC%8B96%EF%BC%8B95%EF%BC%8D94%EF%BC%8D93%EF%BC%8B%EF%BC%8E%EF%BC%8E%EF%BC%8E%EF%BC%8B8%EF%BC%8B7%EF%BC%8D6%EF%BC%8D5%EF%BC%8B4%EF%BC%8B3%EF%BC%8D2%EF%BC%8D12%EF%BC%8E0%EF%BC%8E2001%C3%970%EF%BC%8E19981998%EF%BC%8D0%EF%BC%8E1998%C3%970%EF%BC%8E20012001)
四、计算题:快急!不能直接写得数!1.100+99-98-97+96+95-94-93+...+8+7-6-5+4+3-2-12.0.2001×0.19981998-0.1998×0.20012001
四、计算题:快急!不能直接写得数!
1.100+99-98-97+96+95-94-93+...+8+7-6-5+4+3-2-1
2.0.2001×0.19981998-0.1998×0.20012001
四、计算题:快急!不能直接写得数!1.100+99-98-97+96+95-94-93+...+8+7-6-5+4+3-2-12.0.2001×0.19981998-0.1998×0.20012001
1、原式=2+2+2+2+.+2+2=2*50=100
2、原式=0.2001*0.1998*(1+0.00001998-1-0.00002001)=
个
1,100+99-98-97=4,其它四个数分开100/4=25,所以4×25=100
2,0.2001×0.19981998-0.1998×0.20012001
=0.2001×(0.1998+0.00001998)-0.1998×(0.2001+0.00002001
)=0.2001×0.00001998-0.1998×0.00002001
=0(备注两个乘数提出小数后是一样的)
1:100+99-98-97=4,其它四个数分开100/4=25,所以4×25=100
2:0.2001×0.19981998-0.1998×0.20012001
=0.2001×(0.1998+0.00001998)-0.1998×(0.2001+0.00002001)
=0.2001×0.1998+0.2001×0.00001998-0.1998×0.2001-0.19...
全部展开
1:100+99-98-97=4,其它四个数分开100/4=25,所以4×25=100
2:0.2001×0.19981998-0.1998×0.20012001
=0.2001×(0.1998+0.00001998)-0.1998×(0.2001+0.00002001)
=0.2001×0.1998+0.2001×0.00001998-0.1998×0.2001-0.1998×0.00002001
=0.2001×0.00001998-0.1998×0.00002001
=0.2001×(0.00001998×10000)-0.1998×(0.00002001×10000)
=0.2001×0.1998-0.1998×0.2001
=0
收起
0.2001×0.19981998-0.1998×1.20012001 =(0.2001×0.1998)(1×1.0001-1×1.0001) =0
我是路过的。。。。。