题目
用递等式计算
①1- ÷2.5
② ×(15- )
③ ÷( + )
④3-1÷ ×
⑤2-1.5× +
⑥0.12÷ +0.13×
答案:①1-56÷2.5 =1-56×25 =1-13 =23; ②115×(15-56) =115×15-115×56 =1-118 =1718; ③112÷(14+23) =112÷1112 =111; ④3-1÷73×314 =3-37×314 =3-998 =28998; ⑤2-1.5×16+34 =2-32×16+34 =2-14+34 =212; ⑥0.12÷38+0.13×83 =0.12×83+0.13×83 =(0.12+0.13)×83 =0.25×83 =14×83 =23。