脱式计算(能简算的要简算) ①2009×97.75+4018×1.125 ②4.02×8.1×
③9999×8888÷6666 ④3.6×1994
⑤(1+0.93+0.34)×(0.93+0.34+0.65)-(1+0.93+0.34+0.65)×(0.93+0.34) ⑥0.
|
①2009×97.75+4018×1.125,
=2009×97.75+2009×2×1.125,
=2009×(97.75+2.25),
=2009×100,
=200900;
②4.02×8.1×
÷(0.6×0.81),3 5
=4.02×8.1×0.6÷0.6÷0.81,
=4.02×(8.1÷0.81)×(0.6÷0.6),
=4.02×10×1,
=40.2;
③9999×8888÷6666,
=9999×8×1111÷6666,
=9999×8×(1111÷6666),
=9999×8×
,1 6
=13332;
④3.6×1994
+2006.9×62 5
,2 5
=3.6×1994.4+2006.9×6.4,
=3.6×(2000-5.6)+(2000+6.9)×6.4,
=(3.6+6.4)×2000-3.6×5.6+6.9×6.4,
=10×2000+6.9×6.4-3.6×5.6,
=20000+0.3×23×0.8×8-0.3×12×0.8×7,
=20000+0.3×0.8×(23×8-12×7),
=20000+0.24×(184-84),
=20000+24,
=20024;
⑤设1+0.93+0.34=a,1+0.93+0.34+0.65=b,
(1+0.93+0.34)×(0.93+0.34+0.65)-(1+0.93+0.34+0.65)×(0.93+0.34),
=a×(b-1)-b×(a-1),
=ab-a-ab+b,
=b-a,
=(1+0.93+0.34+0.65)-(1+0.93+0.34),
=0.65;
⑥0.
+0.1• 3
+0.1• 1
+0.1• 2
+0.1• 3
+0.1• 4
,• 5
=
+30 90
+10 90
+11 90
+12 90
+13 90
,14 90
=1.