①
②
③
④
①5.8﹣1.9﹣2.1
②×2.5××4
③÷(﹣)×
④83×0.75+17÷
①600﹣300÷20×5
②(4.8﹣3.8÷2)×0.3
③3.45×99×2+6.9
④(8+ )÷4
⑤ ÷9+ ×
⑥ ÷[ ×( - )]