1、市一小五數(shù)組,看誰算得快,0.32100,240.24,150.15,0.40.5,1.258,2.54,0.245,0.60.1,= 32,= 24.24,= 14.85,= 0.2,= 10,= 10,= 1.2,= 0.06,0.50.2= 500.2= 5000.2=,0.1,10,100,2.50.4,= 1,0.2540,= 10,1.250.8,= 1,1.2580,= 100,2、在括號(hào)里填上適當(dāng)?shù)臄?shù)。,(1)0.32=4( ) (2)1.02=1+( ),(3)0.99=1-( ) (4)9.8=( )-( ),0.08,10,0.01,0.02,0.2,4.21.69 2.

2、50.770.4（ ） 6.13.6+3.93.6（ ）,填一填,1.69,4.2,2.5,0.4,0.77,6.1,3.9,3.6,3、乘法有哪些運(yùn)算定律？ 怎樣用字母式子表示？,乘法交換律：,ab=ba,乘法結(jié)合律：,(ab) c=a (bc),乘法分配律：,(a+b) c=ac+bc,學(xué)習(xí)目標(biāo)： 1、能正確的進(jìn)行小數(shù)乘法的簡 便運(yùn)算。 2、能根據(jù)不同題型，靈活的進(jìn)行簡便計(jì)算。,揭題示標(biāo),看誰算得巧,(234)15,25734,10232,= 25473 = 10073 = 7300,= 23(415) = 2360 = 1380,= (100+2)32 = 10032+232 = 320

3、0+64 = 3264,基礎(chǔ)練習(xí),7.60.8+0.27.6,0.2536,0.8599,0.25321.25,= 7.6(0.8+0.2) = 7.61 = 7.6,= 0.2549 = 19 = 9,= 0.85(100-1) = 0.85100-0.851 = 85-0.85 = 84.15,=0.25481.25 = (0.254)(8 1.25) = 110 = 10,0.258.54,1.288.6+0.728.6,= 0.2548.5 = 18.5 =8.5,= (1.28+0.72) 8.6 = 28.6 =17.2,0.42160+361.6-34 3.2 5.4450+46

4、45 1.288.6+0.828.6-0.86,拓展鞏固,通過本節(jié)課的學(xué)習(xí)，你有哪些新的收獲？,小數(shù)計(jì)算應(yīng)注意的問題： 一審：審清題目。 二看：觀察數(shù)字特征，選擇合理的運(yùn)算律。 三算：認(rèn)真計(jì)算。 四查：查運(yùn)算順序；查數(shù)字；查每一步的計(jì)算。,4.53.6-3.64.1 （1.8-0.25）4 =4.504.1 =1.8-0.254 =0 =1.8-1 =0.8,數(shù)學(xué)醫(yī)院,當(dāng)堂檢測,( ),( ),(1)0.0340.50.8 (2)0.1256.80.8 (3)2.80.25,下面各題怎樣計(jì)算簡便就怎樣算.,（5）760.08+0.27.6,（4）0.8599+0.85,= 7.60.8+0.27.6 = 7.6(0