四年級(jí)數(shù)學(xué)下冊(cè) 6.小數(shù)的加法和減法(第1課時(shí))小數(shù)加減混合運(yùn)算課件 新人教版.ppt
小數(shù)加、減法的意義和法則,復(fù)習(xí),少先隊(duì)采集中草藥每一小隊(duì)采集了3735克,第二小隊(duì)采集了4075克兩個(gè)小隊(duì)一共采集了多少克?,37354075,3735,4075,7810,7810(克),1,少先隊(duì)采集中草藥每一小隊(duì)采集了3735千克,第二小隊(duì)采集了4075千克兩個(gè)小隊(duì)一共采集了多少千克?,3.7354.075,3735,4075,7810,7.81(千克),反饋練習(xí):,0.604+0.825=,7.58+26.08=,0.604,+0.825,1.429,7.58,+26.08,33.66,1.429,33.66,少先隊(duì)采集中草藥兩個(gè)小隊(duì)一共采集了781千克第一小隊(duì)采集了3375千克,第二小隊(duì)采集了多少千克?,7.813.375,7.81,3.375,4.075,千分位看作0,=4.075(千克),2,0,反饋練習(xí):,7.81-4.075=,0.4-0.375=,7.81,-4.075,3.735,0.4,-0.375,0.025,3.735,0.025,小數(shù)加、減法的計(jì)算法則,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),一、選擇題,1127.2比一個(gè)數(shù)少72,這個(gè)數(shù)是(),120,55.2,199.2,練習(xí),一、選擇題,1127.2比一個(gè)數(shù)少72,這個(gè)數(shù)是(),120,55.2,199.2,一、選擇題,1127.2比一個(gè)數(shù)少72,這個(gè)數(shù)是(),120,55.2,199.2,一、選擇題,1127.2比一個(gè)數(shù)少72,這個(gè)數(shù)是(),120,55.2,199.2,一、選擇題,2()100571010,4.3,43,0.43,一、選擇題,2()100571010,4.3,43,0.43,一、選擇題,2()100571010,4.3,43,0.43,一、選擇題,2()100571010,4.3,43,0.43,二、直接寫出下列各式的得數(shù),170.3,0.60.06,1.10.01,2.22.02,90.9,6.436,5.55,100.09,10.999,5.025.02,17.3,0.54,4.22,1.09,8.1,9.91,0.001,0.5,42.4,0,三、豎式計(jì)算,4.8450.99=,36.879.85=,4.845,+0.99,5.835,36.87,+9.85,46.72,5.835,46.72,三、豎式計(jì)算,5000.0756=,111.0418.47=,500,-0.0756,111.04,-18.47,499.9244,92.57,499.9244,92.57,