小數(shù)加減乘除運(yùn)算方法對(duì)比市公開課金獎(jiǎng)市賽課一等獎(jiǎng)?wù)n件

1、+-小數(shù)計(jì)算方法對(duì)比第1頁(yè)+嗨，我是加號(hào)。在計(jì)算小數(shù)加法運(yùn)算時(shí)，小數(shù)點(diǎn)一定要對(duì)齊喲！ 3.85+ 0.2 4.05 第2頁(yè)-嗨，我是減號(hào)。我和加法一樣，在計(jì)算小數(shù)減法運(yùn)算時(shí)，小數(shù)點(diǎn)也一定要對(duì)齊喲！ 56.7 3.98 52.72第3頁(yè)嗨，我是乘號(hào)。我和加法可不一樣，在計(jì)算小數(shù)乘法運(yùn)算時(shí)，末尾對(duì)齊，小數(shù)點(diǎn)在計(jì)算過程中沒有用。不過計(jì)算出得數(shù)后，這時(shí)小數(shù)點(diǎn)要發(fā)揮作用了。 0.4 8 3 0.0 6 0.0 2 8 9 83位2位5位第4頁(yè)嗨，該我出場(chǎng)了。我計(jì)算方法要與整數(shù)除法看齊。要注意小數(shù)點(diǎn)移動(dòng)位置。1 4 3 8 5.22 81 0 59 87 07 0075.第5頁(yè)運(yùn)算 對(duì) 齊小數(shù)點(diǎn)次序加減乘

2、除相同數(shù)位對(duì)齊（小數(shù)點(diǎn)對(duì)齊）相同數(shù)位對(duì)齊（小數(shù)點(diǎn)對(duì)齊）末位對(duì)齊商小數(shù)點(diǎn)與被除數(shù)小數(shù)點(diǎn)對(duì)齊對(duì)齊對(duì)齊不一定對(duì)齊對(duì)齊由低位到高位由低位到高位由低位到高位由高位到低位列豎式計(jì)算方法對(duì)比第6頁(yè)3.11+2.22=26-13.7=爭(zhēng)當(dāng)小神算:)注意:小數(shù)點(diǎn)對(duì)齊!4.2+13.6+5.8=12.06-3.25-6.75=(a+b)+c=a+(b+c)a-b-c=a-(b+c)第7頁(yè)3.84=豎式計(jì)算我最快:)0.315.2=注意:末尾對(duì)齊!6.9700=注意:先落0再點(diǎn)小數(shù)點(diǎn)!0.125X13.7X84.50.9+5.50.97.3-7.30.1第8頁(yè)13.53=1925=1、先把除數(shù)變成整數(shù)；2、被除數(shù)和除數(shù)同時(shí)擴(kuò)大相同倍數(shù)；3、商小數(shù)點(diǎn)要與移動(dòng)后被除數(shù)小數(shù)點(diǎn)對(duì)齊。豎式計(jì)算我最快:)1、按整數(shù)除法計(jì)算；2、商小數(shù)點(diǎn)與被除數(shù)小數(shù)點(diǎn)對(duì)齊；3、除到小數(shù)部分有余數(shù)時(shí)，可添0繼續(xù)除。4、個(gè)位不夠商1用0占位。0.