cuboidWhichthingsarecuboidinourlife？Howmanysurfaces(面）dothecubiodhave?Indifferentpointofview,howmanysurfacescanyousee?Surface（面）Edge（棱）Twosurfacesareassociatedwitheachotherintoaline.Itmeansedge.surfaceedgepeakThreeedgesareassociatedinapoint.Itmeanspeak.Howmanyedgesandpeaksdoacuboidhave?Whatcharacteristicofthecuboid’ssurfacesandedges?CuboidSurfaceEdgePeakCuboidSurfaceEdgePeaksixCuboidSurfaceEdgePeaksixtwelveCuboidSurfaceEdgePeaksixtwelveeightThecuboud’ssixsurfacesareallrectangles。SpecialThecuboid’srelativesurfacesaresame.Thecuboid’ssixsurfacesareallrectangles。3groupsofedgesineachgroup,andthelengthofthe4edgesisequal.Thecuboid’srelativesurfacesaresame,sodotheedges3groupsofedgesineachgroup,andthelengthofthe4edgesisequal.Thelengthofthethreeedgesofthecuboidiscalledlength（長）,width（寬）,height（高）.lengthwidthheightPractice7cm4dm8mm20mm8mm6dm5dm4cm3cmlength:7cmwidth:4cmheight:3cmlength:4dmwidth:6dmheight:5mlength:8mmwidth:20mmheight:8mm

長，寬，高都相等的長方體叫正方體，也叫立方體。討論：

1.正方體的面有幾個(gè)?有什么特點(diǎn)？

2.正方體的棱有幾條?有什么特點(diǎn)?3.正方體的頂點(diǎn)有幾個(gè)?長方體和正方體的認(rèn)識cuboidandcube討論：

1.正方體的面有幾個(gè)?有什么特點(diǎn)？

2.正方體的棱有幾條?有什么特點(diǎn)?3.正方體的頂點(diǎn)有幾個(gè)?長方體和正方體有哪些相同點(diǎn)，有哪些不同點(diǎn)？

名稱

長方體正方體

面?zhèn)€數(shù)

形狀

棱條數(shù)長度

頂點(diǎn)個(gè)數(shù)長方體和正方體的特征6個(gè)6個(gè)

每個(gè)面都是長方形（可能有兩個(gè)面是正方形）

都是正方形

12條棱每4條棱相等（可能有8條棱相等）

12條每條相等8個(gè)8個(gè)長方體正方體長方體3