四年級小數(shù)簡便運(yùn)算與答案

1、一、用簡便方法計算下面各題：一、用簡便方法計算下面各題：48.7+5.6+11.3 43.21+98.76+56.79+1.24 5.48+3.9948.7+5.6+11.3 43.21+98.76+56.79+1.24 5.48+3.996.3+15.4+0.09+3.7+14.6 56.8+22.8 34.656.3+15.4+0.09+3.7+14.6 56.8+22.8 34.650.990.990.970.9734.534.52.98 45.72.98 45.710.4 57.310.4 57.327.8 27.8 =48.7+11.3+5.6=48.7+11.3+5.6=60+5.

2、6=60+5.6=65.6=65.6=(43.21+56.79)+(98.76+1.24)=(43.21+56.79)+(98.76+1.24)=100+100=100+100=200=200=5.48+(4=5.48+(40.01)0.01)=5.48+4=5.48+40.010.01=9.47=9.47=(6.3+3.7)+(14.6+15.4)+0.09=(6.3+3.7)+(14.6+15.4)+0.09 =40+0.09=40+0.09=40.09=40.09=56.8+23=56.8+230.20.2=79.8=79.80.20.2=79.6=79.6=34.65=34.651 1

3、1+(0.01+0.03)1+(0.01+0.03)=32.65+0.04=32.65+0.04=32.69=32.69=34.5=34.53+0.023+0.02=31.5+0.02=31.5+0.02=31.52=31.52=45.7=45.710100.40.4=35.7=35.70.40.4=35.3=35.3=57.3=57.328+0.228+0.2=29.3+0.2=29.3+0.2=29.5=29.567.6867.687.37.32.7 3.652.7 3.651.281.280.370.371.771.7719.82619.8261.1731.1735.2485.2483.

4、405 130.83.405 130.835.9+5.935.9+5.923.97+0.9+6.8 23.9+6.7823.97+0.9+6.8 23.9+6.783.9 31.613.9 31.6121.2721.271.611.61=67.68=67.68(7.3+2.77.3+2.7) =67.68=67.681010=57.68=57.68=3.65=3.65(1.28+0.371.28+0.37) 1.771.77 =3.65=3.651.65 1.65 1.771.77 =0.23=0.23=19.826=19.826(1.173+5.248+3.4051.173+5.248+3.

5、405 )=19.826=19.8269.8269.826 =10=10=130. 8=130. 8(35.935.95.95.9) =130.8=130.83030=100.8=100.8=23.97+1+ =23.97+1+ 70.30.3=31.97=31.970.30.3=31.67=31.67=23.9=23.93.9+6.783.9+6.78 =20+6.78=20+6.78=26.78=26.78=31.61=31.611.61 1.61 21.2721.27=30=3021.2721.27=8.73=8.7327.6427.64(5.79+1.64) 23.12(5.79+1.

6、64) 23.12(10.12(10.123.67) 3.67) 20.6520.65(17.1(17.11.35) 32.75+(15.251.35) 32.75+(15.2510.68)10.68)30.1630.1623.28+15.28 0.2523.28+15.28 0.254.784.784 0.984 0.982.52.5=27.64=27.641.64 1.64 5.795.79=26=265.795.79=20.21=20.21=23.12=23.1210.12+3.6710.12+3.67=13+3.67=13+3.67=16.67=16.67=20.65+1.35=20.

7、65+1.3517.117.1=22=2217.117.1=4.9=4.9=32.75+15.25=32.75+15.2510.6810.68=48=4810.6810.68=37.32=37.32=30. 16=30. 16(23.2823.2815.2815.28) =30.16=30.168 8=22.16=22.16=0.25=0.254 44.784.78=1=14.784.78=4.78=4.78= = (1 10.020.02) 2.52.5=1=12.52.50.020.022.52.5=2.5=2.50.050.05=2.45=2.454.524.520.45+5.480.4

8、5+5.480.45 420.45 423.9 3.9 1.4 1.499+1.499+1.40.250.257 73.6 1.253.6 1.2513131.6 10.21.6 10.20.410.412.52.512.512.532 4232 4267+4.267+4.2330 8.37330 8.3716168 8=0.25=0.257 7(4(40.90.9）=0.25=0.254 47 70.90.9=1=17 70.90.9=6.3=6.3=1.25=1.251313(8(80.20.2）=1.25=1.258 813130.20.2=10=1013130.20.2=26=26=

9、(10+0.2= (10+0.2）0.410.41=10=100.41+0.20.41+0.20.410.41=4.1+0.082=4.1+0.082=4.182=4.182=(4.52+5.48=(4.52+5.48）0.450.45=10=100.450.45=4.5=4.5= 42= 42(4(40.10.1）=42=424 442420.10.1=168=1684.24.2=163.8=163.8=1.4=1.4(99+1(99+1）=1.4=1.4100100=140=140=2.5=2.512.512.5(8(84 4）=(2.5=(2.54)4)(12.5(12.58)8)=10

10、=10100100=1000=1000=42=4267+4267+423333=42=42(67+33(67+33）=42=42100100=4200=4200=8.37=8.37(16(168 8）=8.37=8.372 2=16.74=16.7428.728.70.35 3100.35 3102.52.54 11.24 11.2 9.6 9.62.42.4560560(140(1408) 5.68) 5.67 74 914 910.1250.1252.382.384.1+5.84.1+5.82.38+0.238 28.72.38+0.238 28.71.61.628.728.7=28.7=

11、28.7(0.7(0.70.50.5）=28.7=28.70.70.70.50.5=41=410.50.5=82=82=310=310(2.5(2.54 4）=310=3101010=31=31=11.2=11.2(9.6(9.62.42.4）=11.2=11.24 4=2.8=2.8=560=5601401408 8=4=48 8=32=32=5.6=5.64 47 7=1.4=1.47 7=9.8=9.8=(91=(918)8)(0.125(0.1258 8）=728=7281 1=728=728=2.38=2.384.1+5.84.1+5.82.38+2.382.38+2.380.10.

12、1=2.38 =2.38 (4.1+5.8+0.1(4.1+5.8+0.1）=2.38=2.381010=23.8=23.8= 28.7= 28.728.728.71.61.6=1=11.61.6=1.6=1.611110.250.2510100.25 (80+5.6)0.25 (80+5.6)8 8 =(11 =(11 10)10)0.250.25=1=10.25 0.25 =4=4=80=808+5.68+5.68 8=10+0.7 =10+0.7 =10.7=10.77.87.8(1.001(1.0010.26)0.26)0.26 3.5+17.80.26 3.5+17.899+14.3

13、99+14.31001009.59.50.98+9.50.98+9.52 282 2811.11+99.9911.11+99.998 8=7.8=7.81.0011.001(0.26(0.260.26) 0.26) =7.8=7.81.0011.001=7.8078=7.8078=(3.5+14.3)+17.8=(3.5+14.3)+17.89999=17.8=17.8(1+99(1+99）=17.8=17.8100100=1780=1780=100=1000.980.989.5+9.59.5+9.52 2=9.5=9.5(98+2(98+2）=9.5=9.5100100=950=950=28

14、=2811.11+11.1111.11+11.119 98 8=28=2811.11+11.1111.11+11.11(9(98)8)=11.11=11.11(28+72(28+72）=11.11=11.11100100=1111=11117.67.618+2.318+2.32.4 1.622.4 1.628 8(3.62(3.622.37)2.37)0.380.387.6+0.387.6+0.382.5+0.382.5+0.382 362 362.54+1.82.54+1.849.249.21994+199.4+19.94+1.9941994+199.4+19.94+1.994=1.62=1

15、.628 81.251.25=1.62=1.62(8(81.251.25）=1.62=1.621010=0.162=0.162=0.38=0.387.6+0.387.6+0.380.4+0.380.4+0.382 2=0.38=0.38(7.6+0.4+2)(7.6+0.4+2)=0.38=0.381010=3.8=3.8=1.8=1.820202.54+1.82.54+1.849.249.2=1.8=1.8(20(202.54)+1.82.54)+1.849.249.2=1.8=1.8(50.8+49.2)(50.8+49.2)=1.8=1.8100100=180=180=2000+200+

16、20+2=2000+200+20+26 60.60.60.060.060.0060.006=2222=22226.6666.666=2215.334=2215.334=0.7=0.71+(21+(22)2)0.7+0.70.7+0.73+23+20.0.7 7=0.7=0.7(1+4+3+2)(1+4+3+2)=0.7=0.71010=7=70.7+20.7+21.4+2.1+21.4+2.1+20.70.7(0.375(0.37510110137.5)37.5)37.5 1.137.5 1.11.11.111111.11.11.11.11.11.11999199919981998199819

17、9819981998199919991999199949.549.513.513.50.50.549.5+50.549.5+50.51313=0.375=0.375(101(1011)1)37.5 37.5 =0.375=0.37510010037.5 37.5 =37.5=37.537.5 37.5 =1=1=1.1=1.11.11.1(11(111)1)1.11.1=1.1=1.111111.11.1=1.1=1.1(11(111)1)=11=11=1999=199919981998100011000119981998199919991000110001=0=0999999999+1999

18、999+1999= 999= 999(1000(10001)+19991)+1999= 999= 999100010001 1999+1999999+1999=999000=999000999+1999999+1999=1000000=1000000=49.5=49.5(13.5(13.50.5)+50.50.5)+50.51313=49.5=49.513+50.513+50.513 13 =(49.5+50.5)=(49.5+50.5)1313=1300=1300 111 11136+88836+8888 8=111=11136+11136+1118 88 8=111=111(36+64)(

19、36+64)=11100=11100989898+9798+97979798989797979796 8896 880.1250.1251234123498769876123312339877987798+9798+97969695+94+9395+94+93929291+6+591+6+54 43+2+13+2+1=98=989898989897+9797+979797979796 96 =98=98(98(9897)+9797)+97(97(9796) 96) =98=981+971+971 1=197=197=(80+8)=(80+8)0.125 0.125 =80=800.125+80

20、.125+80.1250.125=10+1=10+1=11=11=1233=12339876+19876+198769876(1233(12339876+12339876+12331)1)=9876=987612331233=8643=8643(8.4+8.4+8.4+8.4)(8.4+8.4+8.4+8.4)2.52.5=8.4=8.44 42.5 2.5 =8.4=8.4(4(42.5)2.5)=84=84= (98+97= (98+97969695)+(94+9395)+(94+93929291)+(6+591)+(6+54 43)+2+13)+2+1=4=4(98(982)2)4 4+

21、2+1+2+1=4=424+2+124+2+1=99=990.9+0.99+0.999+0.9999 12.90.9+0.99+0.999+0.9999 12.90.72+43.50.72+43.53.63.60.2680.2688.888.882.682.684.44 1.1+1.3+1.5+9.7+9.94.44 1.1+1.3+1.5+9.7+9.9117.8117.82.32.34.884.880.23 333330.23 333333333333333=(1+1+1+1)=(1+1+1+1)(0.1+0.01+0.001+0.0001)(0.1+0.01+0.001+0.0001)

22、=4=40.11110.1111=3.8889=3.8889=(12.9=(12.95)5)(0.72(0.725)+43.55)+43.53.63.6=64.5=64.53.6+43.53.6+43.53.63.6=(64.5+43.5)=(64.5+43.5)3.63.6=30=30=(0.268=(0.2682.68)2.68)(8.88(8.884.44)4.44)=0.1=0.12 2=0.2=0.2=(1.1+9.9)=(1.1+9.9)2 24545=5.5=5.54545=247.5=247.5=117.8=117.82.32.348.848.82.32.3=(117.8=(117.848.8)48.8)2.32.3=69=692.32.3=30=300.2