995-640:8-520 280:7+(861-599)
995 - 640 : 8 - 520 = 395 1) 640 : 8 = 80 2) 995 - 80 = 915 3) 915 - 520 = 395 280 : 7 + (861 - 599) = 302 1) 861 - 599 = 262 2) 280 : 7 = 40 3) 262 + 40 = 302
1)640/8=80 995-80=915 915-520=395 2) 861-599=262 280/7=40 262+40=302