四年级数学简便计算题及答案解析.docx

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1、四年级数学简便计算题及答案:1）125×（17×8）×4               =125×8×4×17                        =1000×68                                    =68000 2）375×480+6250×48 =480×(375＋625)  =480000 3）25×16×125                                  =25×2×8×125                                     

2、 =50000                                                                                                  4）13×99   =13×(100－1)=1300－13=12875）75000÷125÷15=75×1000÷125÷15          =75÷15×1000÷125=5×8=40 6）7900 ÷ 4 ÷ 25 =7900÷(4×25) =79    7）150×40÷50=150÷50×40   =3×

3、40  =120      8）5600÷（25×7）=56×100÷25÷7=56÷7×100÷25=32                                                  9）210÷42×6=210÷7÷6×6 =30                                                 10）39600÷25=396×100÷25 =396×4=1584 11）67×21＋18×21+85×79            =21×(67+18)+85×79=21

4、×85+85×79                                  =85×(21+79)=8500 12）321×81+321×19=321×(81+19) =3210013）222222×999999=222222×(1000000－1) =222222000000－222222 =222221777778                                                        14）333333×333333   =111111×999999=111111×(1

5、000000－1)=111111000000－111111=11111088888915）56000÷（14000÷16）         =56000÷14000×16                            =4×16                                     =64                                                                                     16）654321×909090+6543

6、21×90909=654321×999999  =654321×(100000－1)=654321000000－654321=65432034567917）34×3535－35×3434=34×35×101－35×34×101=0                                                                                                                  18）27000÷125=27×1000÷125=27×8=21619

7、）345345÷15015=345×1001÷(15×1001)=345÷15×1001÷1001=23                                                       20）347+358+352+349=350×4－3+8+2－1=1400+6=140621）75×45+17×25                  =25×3×45+17×25                         =25×(135+17)                              

8、 =25×152                                  =25×4×38=3800  22)599996+49997+3998+407+89=600000+50000+4000－4－3－2+407+89=65400+487=65887 23）（48×75×81）÷（24×25