【沪教版数学总结】数与计算

数轴

时间：1世纪=100年&nbsp; &nbsp;1年=12月&nbsp; &nbsp;1天=24时&nbsp; &nbsp;1时=60分&nbsp; &nbsp;1分=60秒&nbsp; &nbsp;1时=3600秒<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 大月(31天)有：1,3,5,7,8,10,12<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 小月(30天)有：4,6,9,11<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 平年：2月有28天，全年365天。 闰年：2月有29天，全年366天

长度：1千米（km）=1000米（m）&nbsp; &nbsp;1米（m）=10分米（dm）&nbsp; &nbsp;1分米（dm）=10厘米（cm）<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1厘米（cm）=10毫米（mm）

面积： 1平方千米（k㎡）=100公顷（h㎡）&nbsp; &nbsp;1公顷（h㎡）=10000平方米（㎡）<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1平方米（㎡）=100平方分米（d㎡）&nbsp; &nbsp;1平方分米（d㎡）=100平方厘米（c㎡）<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1平方厘米（c㎡）=100平方毫米（m㎡）

体积：1立方米（m³）=1000立方分米（dm³）=1000升（L）&nbsp; &nbsp;1立方分米（dm³）=1000立方厘米（cm³） =1升（L）<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1立方厘米（cm³）=1毫升（mL）&nbsp; &nbsp; 1升=1000毫升（mL）

质量：&nbsp;1吨（t）=1000千克（kg）&nbsp; &nbsp;1千克(kg)=1000克（g）&nbsp; 1千克(kg)=1公斤

人民币：1元=10角&nbsp; &nbsp;1角=10分&nbsp; &nbsp;1元=100分

加

减

乘

除

利用四则运算的规律：&nbsp; &nbsp;比如：48 ➗ 2x = 12<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;利用除法规则：被除数 ➗&nbsp; 除数 = 商<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;所以，除数 = 被除数 ➗ 商<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2x = 48 ➗ 12<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2x = 4<br>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;x = 2

等式不变性：把等式左右两边看成一个整体

比较大小

加减