Answers:
13. D. 35,815 + 23,688 = 59,503
14. C. 33,165 + 45,526 = 78,691
15. C. 35,518 + 41,275 = 76,793
16. B. 156,856 + 123,534 = 280,390
17. C. 97,021 - 14,875 = 82,146
18. B. 32,365 + 24,248 = 56,613
19. C. 42,634 + 27,368 = 70,002
20. 43,837 (113,467 - 35,382 - 34,248 = 43,837)
