问题
解答题
递等式计算.(能简算的要简算) 19.67-(1.67+2
(4-3.6×
3.5×
6.4×1.25×2.5 2008÷2009×2010. |
答案
(1)19.67-(1.67+2
)-12 9
,7 9
=19.67-1.67-2
-12 9
,7 9
=(19.67-1.67)-(2
+12 9
),7 9
=18-4,
=14;
(2)(4-3.6×
)÷2 3
,4 5
=(4-2.4)÷
,4 5
=1.6÷
,4 5
=2;
(3)
×11 18
+2 7
×11 7
,5 18
=
×11 18
+2 7
×11 18
,5 7
=
×(11 18
+2 7
),5 7
=
;11 18
(4)3.5×
+5.5×80%+0.8,4 5
=3.5×0.8+5.5×0.8+0.8,
=(3.5+5.5+1)×0.8,
=10×0.8,
=8;
(5)6.4×1.25×2.5,
=(8×0.8)×1.25×2.5,
=(8×1.25)×(8×2.5),
=10×20,
=200;
(6)2008÷2009×2010,
=
×2010,2008 2009
=
×(2009+1),2008 2009
=
×2009+2008 2009
×1,2008 2009
=2008+
,2008 2009
=2008
.2008 2009