《《小數(shù)乘整數(shù)》[1]》由會(huì)員分享,可在線閱讀,更多相關(guān)《《小數(shù)乘整數(shù)》[1](17頁(yè)珍藏版)》請(qǐng)?jiān)谘b配圖網(wǎng)上搜索。
1、單擊此處編輯母版標(biāo)題樣式,,單擊此處編輯母版文本樣式,,第二級(jí),,第三級(jí),,第四級(jí),,第五級(jí),,*,,*,小數(shù)乘整數(shù),人教版五年級(jí)數(shù)學(xué)上冊(cè),,安谷小學(xué) 陳秀芬,1、說(shuō)出下面兩個(gè)算式所表示的意義。,12×7,32×9,2、填空。,,因數(shù),3,,30,,300,,3000,因數(shù),積,5,5,5,5,15,150,1500,15000,,3.5,元,買,3,個(gè)蝴蝶風(fēng)箏需要多少元,?,,,,例,1:,1 0 . 5,3 . 5,+,3.5+3.5+3.5=,3 . 5,3 . 5,10.5,(元),3.5×3=?,3.5,元,=3,元,5,角,3,元,×3=9,元,5,角,×3=15,角,9
2、,元,+15,角,=10.5,元,,,,1 0 .5,元,3 .5,×,3,3.5×3= ?,元,3 5,角,×,3,1 0 5,角,求幾個(gè)相同小數(shù)相加的和,,,等于這個(gè)相同小數(shù)與加數(shù)個(gè)數(shù)相乘的積。,小數(shù)乘整數(shù)的意義與整數(shù)乘法,,的意義相同,都是求幾個(gè)相同,,加數(shù)的和的簡(jiǎn)便運(yùn)算。,0.72×5,=?,,,“,0.72,不是錢數(shù),怎樣計(jì)算?”,0.72,× 5,72,× 5,3.6,0,360,擴(kuò)大到它的,100,倍,縮小到它的,100,倍,末尾的,0,要舍去,,0.72×5=,3,.,6,小數(shù)乘整數(shù)的計(jì)算方法:,先按照整數(shù)乘法計(jì)算,再看,,因數(shù)中有幾位小數(shù),就從積的右,,邊起數(shù)出幾位點(diǎn)上
3、小數(shù)點(diǎn),積的,,小數(shù)部分末尾的,0,要去掉。,算一算,比一比。,,,7,×,,4,,,0.7,×,,4,,,1 2,×,,5,,,1. 2,×,,5,2 8,2.8,6 0,6 .0,觀察這,2,組題,想想與整數(shù)乘整數(shù)有什么不同?,,1.49,×,3,,14.9,×,3,,0.149,×,3,44.7,0.447,4.47,149×3=447,8 2 0,2 .0 5,×,4,2.05×4=,,兩位小數(shù),.,用豎式計(jì)算,8.2,4 6,2 .3,×,1 2,2.3×12=,,2 3,2 7 6,一位小數(shù),.,27.6,,一袋牛奶重,1.25,千克,,64,袋牛奶重多少千克?,1.25×64,=,80,(千克),,答:,64,袋牛奶重,80,千克。,