66509+141400/100+1985=66509+1414+1985=66509+3399=69908

66 509+141 400/(39 839-39 739)+1 985 = 69908

1) 39 839-39 739 = 100

2) 141 400 : 100 = 1414

3) 66 509 + 1414 = 67923

4) 67923 + 1 985 = 69908