420+391=?,215+409=?,426+778=?
724-95=?,971-600=?,942-163=?
57+?=803,249+?=789,345+?=950
83*7=?,9*48=?,774*4=?
459/3=?,504/8=?,918/6=?
---
?-267=893-453,149+154+404+187=?
790-279=?+331,501+328+289-918=?
229+?+395=993,468+470-298-309=?
278+?-583=467,999-252-122-431=?
排队请安静