有理数的加减混合运算(习题课)

兵姆何持冈尸酋萤锚妻脐殿有理数的加减混合运算(习题课)Р加法运算律在加减混合运算中的应用Р例3:计算? (1) -24+3.2-13+2.8-3 ? 解: -24+3.2-13+2.8-3 ? =( -24-13-3 )+( 3.2+2.8)? = -40+6? = -34 ?解题小技巧:运用运算律将正负数分别相加。Р六瓷铱仑椿块影撵敞焉誉襄止盎敬柒沃赠遮搓毅埃秦哦价江仟淌赌觅徊个有理数的加减混合运算(习题课)Р例3:计算(2) 0-1/2 - 2/3 –(-3/4) + (-5/6)Р解: 0- 1/2- 2/3 –(-3/4) + (-5/6)? = 0 - 1/2 - 2/3 + 3/4 - 5/6 ? = (-1/2+3/4) + (-2/3-5/6)? = (-2/4+3/4) + (-4/6-5/6)? = 1/4 + (-3/2)? =1/4-6/4? =-5/4?解题小技巧:分母相同或有倍数关系的分数结合相加Р题翱鹤彝枝撇卒睹天昼沂催彝险敌冕锚剪堑皱悟兑庞疗釜酉柑焙橇玛辖教有理数的加减混合运算(习题课)Р解: ( -0.5) –(-1/4) + (+2.75) –(+5.5)? = (-0.5) + (+0.25) +(+2.75) +(-5.5)? = -0.5 + 0.25 + 2.75 - 5.5? = (-0.5 - 5.5) + (0.25 + 2.75)? = -6 + 3? = -3?解题小技巧:在式子中若既有分数又有小数, 把小数统一成分数或把分数统一成小数Р例3:计算(3) (-0.5) –(-1/4) + (+2.75) –(+5.5)Р囚唆凉闲讯剥蛔稻澳饯升垄播挤筒账赔哲颜蛀济数楼住腐稳纸奄类哑衷屋有理数的加减混合运算(习题课)Р例4、计算:Р孽构枪炯杏办握椭块惭波钠旬冰纬川叹糖措孰醇妨婴阐晨棘键臼匡朗干炮有理数的加减混合运算(习题课)