67800+972-70000:1000 34*10000+600-40000-1 (599999+1):100000*105 (207000:207000+999*7 4*100+305*1000+7*10000-10 (999000+1000):100000*12789

67800+972-70000:1000 = 67800 + 972 - 70 = 68772 - 70 = 68702.34*10000+600-40000-1 = 340000 + 600 - 40000 - 1 = 340600 - 40000 - 1 = 300600 - 1 = 300599.(599999+1):100000*105 = 600000 ÷ 100000 × 105 = 6 × 105 = 630.(207000:207000+999*7 = 1 + 6993 = 6994.4*100+305*1000+7*10000-10 = 400 + 305000 + 70000 - 10 = 305400 + 70000 - 10 = 375400 - 10 = 375390.(999000+1000):100000*12789= 1000000 ÷ 100000 × 12789 = 10 × 12789 = 127890. 10000-1-900 = 9999 - 900 = 9099.(25909+1+100):10 = 26010 ÷ 10 = 2601.207000:10+6000:100 = 20700 + 60 = 20760.50780+4000+2-700 = 54780 + 2 - 700 = 54782 - 700 = 54082.