四年級(jí)數(shù)學(xué)下冊(cè) 第6單元《小數(shù)的加法和減法》小數(shù)的加法和減法課件 新人教版.ppt

,小數(shù)的加法和減法(一),2004雅典奧運(yùn)會(huì),兩名17歲的小將勞麗詩和李婷聯(lián)手為中國代表團(tuán)奪得了本次比賽的第三枚跳水金牌，她們的成績(jī)?yōu)?52.14分。這也是中國代表團(tuán)在本次奧運(yùn)會(huì)上摘得的第十枚金牌。,2004雅典奧運(yùn)會(huì)跳水比賽,勞麗詩李婷,中國隊(duì)領(lǐng)先3.6分。,53.40,49.80,53.4049.80？,筆算,3.6,53.40,49.80,0,6,列堅(jiān)式：,小數(shù)點(diǎn)要對(duì)齊,3,.,小數(shù)部分末尾有0，一般要把0去掉。,中國隊(duì)兩輪的總成績(jī)是多少？,53.40,49.80,58.20,49.20,53.40+58.20？,筆算,111.6,53.40,+,58.20,0,6,列堅(jiān)式：,小數(shù)點(diǎn)要對(duì)齊,1,.,小數(shù)部分末尾有0，一般要把0去掉。,1,1,現(xiàn)在中國隊(duì)領(lǐng)先多少分？,53.40,49.80,58.20,49.20,根據(jù)下面數(shù)據(jù)你能提出什么問題？,53.40,49.80,58.20,49.20,82.80,71.04,86.70,327.78,352.14,76.60,76.70,75.48,試著計(jì)算下面各題。,12.424.36,7.813.735,12.424.36,7.813.735,小數(shù)點(diǎn)對(duì)齊，就是每個(gè)數(shù)位對(duì)齊。,數(shù)位上沒有數(shù)可以添“0”后再進(jìn)行計(jì)算。,0,0,小數(shù)加減法要注意什么？,小數(shù)點(diǎn)要對(duì)齊，也是把數(shù)位對(duì)齊。,得數(shù)的末尾有0，一般要把0去掉。,數(shù)位上沒有數(shù)可以添“0”后再進(jìn)行計(jì)算。,小數(shù)的加減法也可以用計(jì)算器計(jì)算。,這就是小數(shù)點(diǎn)鍵。,口算，比比看，誰算得又對(duì)又快。,3.6+1.4,5.7-2.3,7.6-3.1,4.9+0.5,6.2-2.4,4.9+1.5,0.26+0.35,0.93-0.58,0.37+14.3,計(jì)算,一個(gè)書包的價(jià)格是65.8元，一個(gè)文具盒的價(jià)格是12.6元，這兩樣?xùn)|西一共多少錢？,我的50米賽跑成績(jī)是8.35秒。,我的成績(jī)是8.52秒，我比你慢多少呀？,計(jì)算小數(shù)加、減法，先把各數(shù)的小數(shù)點(diǎn)對(duì)齊(也就是把相同數(shù)位上的數(shù)對(duì)齊)，再按照整數(shù)加減法的法則進(jìn)行計(jì)算，最后在得數(shù)里對(duì)齊橫線上的小數(shù)點(diǎn)，點(diǎn)上小數(shù)點(diǎn)。,小數(shù)加減法,謝謝使用!,