人教版四年级上册数学 亿以内数的近似数 课件（14张PPT）

(共14张PPT)
亿以内数的
近似数
人教版四年级上册
目录
CONTENTS
01
复 习 导 入
02
学 习 新 知
03
总 结 方 法
巩 固 练 习
04
05
总 结 收 获
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
下列各数接近几百几十？
367 523
234 465
159 781
≈370
≈230
≈160
≈520
≈470
≈780
复习导入
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
在日常生活中，人们经常使用近似数
学习新知
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
张阿姨说的18万步是怎么得出的？李阿姨说的22万步又是怎么得出的？
学习新知
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
182068
≈180000
小于5，把它和右面的数全舍去，改写成0
182068
≈18万
180000
190000
185000
182068
学习新知
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
218309
≈220000
大于5，向前一位进1，再把它和右面的数全舍去，改写成0
218309
≈22万
210000
220000
215000
218309
学习新知
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
182068
182068
≈180000
≈18万
218309
≈220000
218309
≈22万
这种求近似数的方法叫“四舍五入”法。是“舍”还是“入”，要看省略的尾数部分的最高位上的数是小于5还是等于或大于5。
总结方法
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
将非整万数改写成用“万”作单位的近似数的方法：
先用“四舍五入”法省略万位后面的尾数
再改写成用“万”作单位的数。
总结方法
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
2018年8月5日，中国科学技术馆接待56023人次。
省略百位后面的尾数
省略千位后面的尾数
省略万位后面的尾数
要求
近似数
原数
56023
56000
56000
60000
巩固练习
Option 01
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
下面画线部分哪些是近似数？哪些是准确数？
（1）小明的身高约140厘米，体重约35千克。（ ）
（2）四（2）班有45人，全校有730人。（ ）
（3）珠穆朗玛峰海拔为8800多米。（ ）
近似数
近似数
准确数
巩固练习
We have many PowerPoint templates tht has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
Option 02
We have many PowerPoint templates that has been specifically designed to help anyone that is stepping into the world of PowerPoint for the very first time.
巩固练习
地区 人口数/人 人口数/万人
上海 24870895
山西 34915616
浙江 64567588
湖南 66444864
广西 50126804
云南 47209277
2487
3492
6457
6644
5013
4721
总结收获
1、先用“四舍五入”法省略万位后面的尾数
2、再改写成用“万”作单位的数。
将非整万数改写成用“万”作单位的近似数的方法：
同学们再见！