Arithmetic Operator Puzzles

#577: 2 _ 3 _ 6 _ 7 = -6 medium #578: 2 _ 3 _ 6 _ 8 = 9 medium #579: 2 _ 3 _ 6 _ 8 = -7 medium #580: 2 _ 3 _ 6 _ 9 = 10 medium #581: 2 _ 3 _ 6 _ 9 = -8 hard #582: 2 _ 3 _ 6 _ 1 = 3 easy #583: 2 _ 3 _ 6 _ 2 = 6 easy #584: 2 _ 3 _ 6 _ 5 = 9 easy #585: 2 _ 3 _ 6 _ 5 = -1 easy #586: 2 _ 3 _ 6 _ 5 = 20 hard #587: 2 _ 3 _ 6 _ 6 = 10 easy #588: 2 _ 3 _ 6 _ 7 = 11 medium #589: 2 _ 3 _ 6 _ 7 = -3 easy #590: 2 _ 3 _ 6 _ 8 = -4 medium #591: 2 _ 3 _ 6 _ 9 = 13 hard #592: 2 _ 3 _ 6 _ 9 = -5 medium #593: 2 _ 3 _ 6 _ 9 = 1 easy #594: 2 _ 3 _ 7 _ 7 = 7 easy #595: 2 _ 3 _ 7 _ 3 = 14 medium #596: 2 _ 3 _ 8 _ 2 = 14 hard #597: 2 _ 3 _ 8 _ 6 = 6 easy #598: 2 _ 3 _ 8 _ 4 = -4 medium #599: 2 _ 3 _ 8 _ 6 = -2 easy #600: 2 _ 3 _ 8 _ 2 = 10 medium #601: 2 _ 3 _ 8 _ 8 = 7 easy #602: 2 _ 3 _ 8 _ 2 = 2 easy #603: 2 _ 3 _ 8 _ 4 = 4 easy #604: 2 _ 3 _ 8 _ 4 = 12 medium #605: 2 _ 3 _ 9 _ 3 = 1 easy #606: 2 _ 3 _ 9 _ 9 = 7 medium #607: 2 _ 3 _ 9 _ 1 = 5 easy #608: 2 _ 3 _ 9 _ 2 = 8 medium #609: 2 _ 3 _ 9 _ 2 = 4 easy #610: 2 _ 3 _ 9 _ 2 = 3 easy #611: 2 _ 3 _ 9 _ 4 = 2 easy #612: 2 _ 3 _ 9 _ 5 = 11 hard #613: 2 _ 3 _ 9 _ 6 = 12 hard #614: 2 _ 3 _ 9 _ 6 = 1 easy #615: 2 _ 3 _ 9 _ 7 = 13 hard #616: 2 _ 3 _ 9 _ 7 = -1 easy #617: 2 _ 3 _ 9 _ 8 = 14 hard #618: 2 _ 3 _ 9 _ 9 = 15 hard #619: 2 _ 3 _ 9 _ 9 = -3 medium #620: 2 _ 4 _ 2 _ 8 = 3 easy #621: 2 _ 4 _ 2 _ 3 = 8 easy #622: 2 _ 4 _ 2 _ 5 = 12 easy #623: 2 _ 4 _ 2 _ 7 = 16 hard #624: 2 _ 4 _ 2 _ 9 = 20 hard