用简便方法计算：①(−321625)×132−(12+23−34−1112)×(−24)；②−999899×198；③(−3)×(−14)+0.25×24.5+(−512)×(−25%)；④-989×（-9）+989×（-19）-（-989）×10．

Question

用简便方法计算：
①(−32(16)/(25))×(1)/(32)−((1)/(2)+(2)/(3)−(3)/(4)−(11)/(12))×(−24)；
②−99(98)/(99)×198；
③(−3)×(−(1)/(4))+0.25×24.5+(−5(1)/(2))×(−25%)；
④-989×（-9）+989×（-19）-（-989）×10．

Answer 1

①(−32(16)/(25))×(1)/(32)−((1)/(2)+(2)/(3)−(3)/(4)−(11)/(12))×(−24)
=-1(1)/(50)+(1)/(2)×24+(2)/(3)×24-(3)/(4)×24-(11)/(12)×24
=-1(1)/(50)+12+16-18-22
=-13(1)/(50)；

②−99(98)/(99)×198
=（-100+(1)/(99)）×198
=-100×198+(1)/(99)×198
=-19800+2
=-19798；

③(−3)×(−(1)/(4))+0.25×24.5+(−5(1)/(2))×(−25%)
=(3)/(4)+6.125+(11)/(8)
=8(1)/(4)；

④-989×（-9）+989×（-19）-（-989）×10
=989×（9-19+10）
=989×0
=0．