北师大版数学四年级下册《小数乘法》课件

,北师大版四年级数学下册,教学目标,本节课我们主要来学习小数乘法，同学们要结合具体的实例理解并掌握小数乘法的计算方法，能够解决相关的实际问题。,Oral calculation,0.342= 0.10.2=0.42=,2.33= 0.60.4=2.110=,1.40.2= 0.50.3=1.10.2=,0.68,0.02,0. 8,6.9,0.24,21,0.28,0.15,0.22,5673= 40885.6 73=5.67.3=,1337= 4811.33.7=1.30.37=,408.8,40.88,4.81,0.481,根据第一个算式的积，写出下面的积,The product has the same decimals as the two factors.,两个因数共有几位小数,积就有几位小数 .,New knowledge,Here is Xiao Mings room.,What information do you know from the picture?,New knowledge,The length is 3.6 meters,The width is 2.8 meters,Can you ask some maths questions?,Whats the area of this room?,3.6 meters,2.8 meters,New knowledge,3.62.8=,Who can estimate(估算)?,Xiao Mings room,3.6 meters,2.8 meters,3.62.8=,10,3 6,10,2 8,100,.,New knowledge,3.62.8=,10,3 6,10,2 8,100,.,New knowledge,One decimal,One decimal,Two decimals,3.6 meter,2.8 meter,1.15 meter,Whats the area of the balcony(阳台)?,1.152.8=,Who Can estimate?,New knowledge,1. 1 5 2. 8,9 2 0 2 3 0,3 2 2 0,Two decimals,One decimal,Three decimals,New knowledge,1、将小数看作整数计算。2、根据两个因数的小数位数， 在积上点上小数点。,总结：,How do we calculate decimal multiplication?,Can you give the decimal points to the following?,.,0.0,Now ,lets do exercise.,给下面的积点上小数点。,Please work out the following products.,=1.2,=5.76,=0.256,=0.384,=4.9,=12.74,两个因数中有一个因数小于1，积就小于另一个因数。两个因数中有一个因数大于1，积就大于另一个因数。,在下面的算式中填上“”或“”。,已知算式36122=43.92丢了小数点，想一