300+600= 536+8= 541-3= 190+( )=200
900-700= 800+200= 620+30= 6+( )=312
130+260= 563-6= 760-720= ( )+563=863
237+6= 580-200= 930-580= 273-( )=203
760-290= 109+5= 1000-20= ( )-180=220