x
4
?
y
12
24
80×30%=
× =
× ÷ × =
3.14×4²=
4000×87.5%=
84÷(1﹣30%)=
①250-250÷25×2
②18÷ ×
③5.2÷0.4÷2.5
④(34- )÷17
⑤4.3×1.75-1.75+ ×6.7
⑥ ×[(72.8-69.6)÷ ]