西师版五年级下册数学知识点归纳总结.pdf

西师版五年级下册数学知识点归纳总结

Chapter1:XXX

1.Divisibility:Thedividend。divisor。andquotientareall

naturalnumbers。andthereisnoremainder.

nshipeenintegersandnaturalnumbers:Integersinclude

naturalnumbers.

2.Factorsandmultiples:XXXwithoutaremainder。the

largernumberisamultipleofthesmallernumber。andthesmaller

numberisafactorofthelargernumber.

XXX:12isamultipleof6.and6isafactorof12.

1)Ifanumberaisdivisiblebyb。thenaisamultipleofb。

andbisafactorofa。XXX.

2)Thenumberoffactorsofanumberisfinite。andthe

smallestfactoris1.andthelargestfactoristhenumberitself。The

methodoffindingfactorsofanumberistofindtheminpairsin

order.

3)Thenumberofmultiplesofanumberisinfinite。andthe

XXXisthenumberitself。Themethodoffindingmultiplesofa

numberistomultiplyitbynaturalnumbersinorder.

4)Characteristicsofmultiplesof2.3.and5:

1)Numberswithaunitdigitof2.4.6.or8areallmultiplesof

2.

2)Ifthesumofthedigitsofanumberisamultipleof3.then

thenumberitselfisamultipleof3.

3)Numberswithaunitdigitof0or5aremultiplesof5.

4)XXXdivisibleby2.3.and5(i.e。multiplesof2.3.and5)is

90.andthesmallestthree-digitnumberis120.Tofindanumber

thatisamultipleof2.3.and5atthesametime。weneedtofinda

multipleof2×3×5=30.

5)Ifanumberisamultipleofboth2and5.thenitsunitdigit

mustbe0.

3.Perfectnumbers:Numberswhosesumoffactors。XXX

itself。XXXitself.

Forexample。thefactorsof6are1.2.and3(excluding6)。

and1+2+3=6.so6isaperfectnumber。Thesmallestperfect

numbersare6and28.

4.Naturalnumberscanbedividedintooddandevennumbers

basedonwhethertheyaredivisibleby2.

Oddnumbers:Numbersthatcannotbedividedby2.They

haveaunitdigit