Arithmetic Operator Puzzles

#1633: 4 _ 2 _ 7 _ 6 = 8 easy #1634: 4 _ 2 _ 7 _ 8 = 6 easy #1635: 4 _ 2 _ 7 _ 9 = 5 easy #1636: 4 _ 2 _ 8 _ 4 = 3 easy #1637: 4 _ 2 _ 8 _ 2 = 4 easy #1638: 4 _ 2 _ 8 _ 1 = 2 easy #1639: 4 _ 2 _ 8 _ 2 = 3 easy #1640: 4 _ 2 _ 8 _ 2 = -1 easy #1641: 4 _ 2 _ 8 _ 3 = 4 easy #1642: 4 _ 2 _ 8 _ 3 = -2 easy #1643: 4 _ 2 _ 8 _ 4 = -3 easy #1644: 4 _ 2 _ 8 _ 5 = 6 easy #1645: 4 _ 2 _ 8 _ 5 = -4 medium #1646: 4 _ 2 _ 8 _ 6 = 7 easy #1647: 4 _ 2 _ 8 _ 6 = -5 medium #1648: 4 _ 2 _ 8 _ 7 = 8 medium #1649: 4 _ 2 _ 8 _ 7 = -6 medium #1650: 4 _ 2 _ 8 _ 8 = -7 medium #1651: 4 _ 2 _ 8 _ 9 = 10 medium #1652: 4 _ 2 _ 8 _ 9 = -8 hard #1653: 4 _ 2 _ 8 _ 4 = 1 easy #1654: 4 _ 2 _ 9 _ 3 = 10 medium #1655: 4 _ 2 _ 9 _ 6 = 7 medium #1656: 4 _ 2 _ 9 _ 3 = -2 medium #1657: 4 _ 2 _ 9 _ 6 = 1 easy #1658: 4 _ 2 _ 9 _ 3 = 11 hard #1659: 4 _ 2 _ 9 _ 1 = 19 hard #1660: 4 _ 2 _ 9 _ 2 = 16 hard #1661: 4 _ 2 _ 9 _ 3 = 15 hard #1662: 4 _ 2 _ 9 _ 3 = 6 easy #1663: 4 _ 2 _ 9 _ 4 = 14 hard #1664: 4 _ 2 _ 9 _ 5 = 13 hard #1665: 4 _ 2 _ 9 _ 7 = 11 hard #1666: 4 _ 2 _ 9 _ 8 = 10 medium #1667: 4 _ 3 _ 2 _ 4 = -2 easy #1668: 4 _ 3 _ 2 _ 8 = -8 medium #1669: 4 _ 3 _ 2 _ 2 = 13 easy #1670: 4 _ 3 _ 2 _ 8 = 3 easy #1671: 4 _ 3 _ 2 _ 1 = 7 easy #1672: 4 _ 3 _ 2 _ 2 = 4 easy #1673: 4 _ 3 _ 2 _ 3 = 9 easy #1674: 4 _ 3 _ 2 _ 3 = 3 easy #1675: 4 _ 3 _ 2 _ 5 = 1 easy #1676: 4 _ 3 _ 2 _ 6 = 12 medium #1677: 4 _ 3 _ 2 _ 7 = 13 medium #1678: 4 _ 3 _ 2 _ 7 = -1 easy #1679: 4 _ 3 _ 2 _ 8 = 14 hard #1680: 4 _ 3 _ 2 _ 8 = -2 easy