Arithmetic Operator Puzzles

#625: 2 _ 4 _ 2 _ 8 = 1 easy #626: 2 _ 4 _ 2 _ 3 = -4 easy #627: 2 _ 4 _ 2 _ 4 = -6 easy #628: 2 _ 4 _ 2 _ 5 = -8 easy #629: 2 _ 4 _ 2 _ 2 = 9 easy #630: 2 _ 4 _ 2 _ 5 = 20 medium #631: 2 _ 4 _ 2 _ 1 = 2 easy #632: 2 _ 4 _ 2 _ 3 = -2 easy #633: 2 _ 4 _ 2 _ 4 = 5 easy #634: 2 _ 4 _ 2 _ 4 = -3 easy #635: 2 _ 4 _ 2 _ 5 = 6 easy #636: 2 _ 4 _ 2 _ 6 = 7 easy #637: 2 _ 4 _ 2 _ 6 = -5 easy #638: 2 _ 4 _ 2 _ 7 = 8 easy #639: 2 _ 4 _ 2 _ 8 = 9 medium #640: 2 _ 4 _ 2 _ 8 = -7 medium #641: 2 _ 4 _ 2 _ 9 = 10 medium #642: 2 _ 4 _ 2 _ 9 = -8 hard #643: 2 _ 4 _ 3 _ 2 = 8 easy #644: 2 _ 4 _ 3 _ 6 = 10 easy #645: 2 _ 4 _ 3 _ 2 = -4 easy #646: 2 _ 4 _ 3 _ 6 = -6 easy #647: 2 _ 4 _ 3 _ 3 = 9 easy #648: 2 _ 4 _ 3 _ 8 = 12 medium #649: 2 _ 4 _ 4 _ 2 = -6 easy #650: 2 _ 4 _ 4 _ 4 = 9 easy #651: 2 _ 4 _ 5 _ 2 = 12 easy #652: 2 _ 4 _ 5 _ 2 = -8 easy #653: 2 _ 4 _ 5 _ 5 = 9 easy #654: 2 _ 4 _ 5 _ 6 = 15 medium #655: 2 _ 4 _ 5 _ 8 = 20 hard #656: 2 _ 4 _ 6 _ 8 = 5 easy #657: 2 _ 4 _ 6 _ 9 = 8 medium #658: 2 _ 4 _ 6 _ 3 = -6 easy #659: 2 _ 4 _ 6 _ 8 = -1 easy #660: 2 _ 4 _ 6 _ 9 = -4 medium #661: 2 _ 4 _ 6 _ 2 = 11 easy #662: 2 _ 4 _ 6 _ 4 = 7 easy #663: 2 _ 4 _ 6 _ 5 = 8 easy #664: 2 _ 4 _ 6 _ 5 = -2 easy #665: 2 _ 4 _ 6 _ 5 = 15 medium #666: 2 _ 4 _ 6 _ 7 = 10 medium #667: 2 _ 4 _ 6 _ 7 = -4 easy #668: 2 _ 4 _ 6 _ 8 = 11 medium #669: 2 _ 4 _ 6 _ 8 = -5 medium #670: 2 _ 4 _ 6 _ 9 = -6 medium #671: 2 _ 4 _ 7 _ 2 = 16 hard #672: 2 _ 4 _ 7 _ 7 = 9 easy