絕對(duì)值與相反數(shù)-課件-課件

絕對(duì)值與相反數(shù)(3)絕對(duì)值與相反數(shù)(3)

數(shù)軸上表示一個(gè)數(shù)的點(diǎn)與原點(diǎn)的距離,叫做這個(gè)數(shù)的絕對(duì)值.什么叫一個(gè)數(shù)的絕對(duì)值回顧與思考數(shù)軸上表示一個(gè)數(shù)的點(diǎn)與原點(diǎn)的距離,叫做這個(gè)數(shù)的絕對(duì)3的絕對(duì)值記作-1.3的絕對(duì)值記作0的絕對(duì)值記作你還記得嗎?3的絕對(duì)值記作你還記得嗎?根據(jù)絕對(duì)值與相反數(shù)的意義填空:____2.36.22.36.200想想看一個(gè)數(shù)的絕對(duì)值與這個(gè)數(shù)本身或它的相反數(shù)有什么關(guān)系?正數(shù)的絕對(duì)值是它本身負(fù)數(shù)的絕對(duì)值是它的相反數(shù)0的絕對(duì)值是0根據(jù)絕對(duì)值與相反數(shù)的意義填空:____2.36.22.36.例1:求下列各數(shù)的絕對(duì)值:+6,-3,0,解:正數(shù)的絕對(duì)值是它本身負(fù)數(shù)的絕對(duì)值是它的相反數(shù)0的絕對(duì)值是0例1:求下列各數(shù)的絕對(duì)值:解:正數(shù)的絕對(duì)值是它本身負(fù)數(shù)的絕對(duì)例2：求下列各數(shù)的絕對(duì)值:+6,-3,,0,想一想:問(wèn)題一:求一個(gè)數(shù)的絕對(duì)值關(guān)鍵看什么?關(guān)鍵是看這個(gè)數(shù)的符號(hào)問(wèn)題二:如何求一個(gè)數(shù)的絕對(duì)值呢?首先要分清這個(gè)數(shù)是正數(shù)、負(fù)數(shù)還是0,其次才能正確地寫(xiě)出它的絕對(duì)值.例2：求下列各數(shù)的絕對(duì)值:想一想:問(wèn)題一:求一個(gè)數(shù)的絕對(duì)值關(guān)1.書(shū)P24第一題.1.書(shū)P24第一題.

議一議

兩個(gè)數(shù)比較大小,絕對(duì)值大的那個(gè)一定大嗎?530350-3-535

兩個(gè)正數(shù),絕對(duì)值大的正數(shù)就大.

兩個(gè)負(fù)數(shù),絕對(duì)值大的反而小.議一議兩個(gè)數(shù)比較大小,絕對(duì)值大的那個(gè)一定大≥用文字語(yǔ)言敘述就是:若一個(gè)數(shù)的絕對(duì)值等于其本身,則這個(gè)數(shù)是非負(fù)數(shù).≤用文字語(yǔ)言敘述就是:若一個(gè)數(shù)的絕對(duì)值等于其本身的相反數(shù),則這個(gè)數(shù)是非正數(shù).≥用文字語(yǔ)言敘述就是:若一個(gè)數(shù)的絕對(duì)值等于其本身,≤用文字語(yǔ)你一定行！相信你自己！1.絕對(duì)值等于5的數(shù)是______.2.絕對(duì)值小于5的負(fù)整數(shù)是______.3.絕對(duì)值不大于5而又不小于2的整數(shù)是______.4.絕對(duì)值不大于5.3而又不小于2的整數(shù)是______.你一定行！相信你自己！1.絕對(duì)值等于5的數(shù)是______.25.已知a>b>0,-a_____-b.6.a、b兩個(gè)有理數(shù)在數(shù)軸上表示的點(diǎn)如下圖所示,則a、b、-a、-b按由小到大的順序排列,并用“<”號(hào)連接起來(lái).a0b5.已知a>b>0,-a_____-b.6.a、b兩個(gè)有理數(shù)1.利用法則求一個(gè)數(shù)的絕對(duì)值；課堂小結(jié)2.學(xué)會(huì)借助絕對(duì)值比較兩個(gè)數(shù)的大小.1.利用法則求一個(gè)數(shù)的絕對(duì)值；課堂小結(jié)2.學(xué)會(huì)借助絕對(duì)值比較絕對(duì)值與相反數(shù)(3)絕對(duì)值與相反數(shù)(3)

數(shù)軸上表示一個(gè)數(shù)的點(diǎn)與原點(diǎn)的距離,叫做這個(gè)數(shù)的絕對(duì)值.什么叫一個(gè)數(shù)的絕對(duì)值回顧與思考數(shù)軸上表示一個(gè)數(shù)的點(diǎn)與原點(diǎn)的距離,叫做這個(gè)數(shù)的絕對(duì)3的絕對(duì)值記作-1.3的絕對(duì)值記作0的絕對(duì)值記作你還記得嗎?3的絕對(duì)值記作你還記得嗎?根據(jù)絕對(duì)值與相反數(shù)的意義填空:____2.36.22.36.200想想看一個(gè)數(shù)的絕對(duì)值與這個(gè)數(shù)本身或它的相反數(shù)有什么關(guān)系?正數(shù)的絕對(duì)值是它本身負(fù)數(shù)的絕對(duì)值是它的相反數(shù)0的絕對(duì)值是0根據(jù)絕對(duì)值與相反數(shù)的意義填空:____2.36.22.36.例1:求下列各數(shù)的絕對(duì)值:+6,-3,0,解:正數(shù)的絕對(duì)值是它本身負(fù)數(shù)的絕對(duì)值是它的相反數(shù)0的絕對(duì)值是0例1:求下列各數(shù)的絕對(duì)值:解:正數(shù)的絕對(duì)值是它本身負(fù)數(shù)的絕對(duì)例2：求下列各數(shù)的絕對(duì)值:+6,-3,,0,想一想:問(wèn)題一:求一個(gè)數(shù)的絕對(duì)值關(guān)鍵看什么?關(guān)鍵是看這個(gè)數(shù)的符號(hào)問(wèn)題二:如何求一個(gè)數(shù)的絕對(duì)值呢?首先要分清這個(gè)數(shù)是正數(shù)、負(fù)數(shù)還是0,其次才能正確地寫(xiě)出它的絕對(duì)值.例2：求下列各數(shù)的絕對(duì)值:想一想:問(wèn)題一:求一個(gè)數(shù)的絕對(duì)值關(guān)1.書(shū)P24第一題.1.書(shū)P24第一題.

議一議

兩個(gè)數(shù)比較大小,絕對(duì)值大的那個(gè)一定大嗎?530350-3-535

兩個(gè)正數(shù),絕對(duì)值大的正數(shù)就大.

兩個(gè)負(fù)數(shù),絕對(duì)值大的反而小.議一議兩個(gè)數(shù)比較大小,絕對(duì)值大的那個(gè)一定大≥用文字語(yǔ)言敘述就是:若一個(gè)數(shù)的絕對(duì)值等于其本身,則這個(gè)數(shù)是非負(fù)數(shù).≤用文字語(yǔ)言敘述就是:若一個(gè)數(shù)的絕對(duì)值等于其本身的相反數(shù),則這個(gè)數(shù)是非正數(shù).≥用文字語(yǔ)言敘述就是:若一個(gè)數(shù)的絕對(duì)值等于其本身,≤用文字語(yǔ)你一定行！相信你自己！1.絕對(duì)值等于5的數(shù)是______.2.絕對(duì)值小于5的負(fù)整數(shù)是______.3.絕對(duì)值不大于5而又不小于2的整數(shù)是______.4.絕對(duì)值不大于5.3而又不小于2的整數(shù)是______.你一定行！相信你自己！1.絕對(duì)值等于5的數(shù)是______.25.已知a>b>0,-a_____-b.6.a、b兩個(gè)有理數(shù)在數(shù)軸上表示的點(diǎn)如下圖所示,則a、b、-a、-b按由小到大的順序排列,并