1
300+200
500
520+3
523
852-3
849
840+30
870
523+7
530
400+200
600
865-4
861
753-9
744
980-70
910
452-30
422
1000-700
300
969-6=
963
526+7
533
520+(8.5)
560
240+(7.6)
282
200+(400+400)
1000
(450-50)+8
408
(452+8)-9
451
(950-10)-40
900
(850+60)-60
850
(300+100)+(900-600)
700
(956-9)-9
938
(852-4)+9
857
(360-20)+(100-60)
380
(350+60)-(5.4)
390