Hard Arithmetic Puzzles

#1611: 4 _ 2 _ 5 _ 8 = 18 hard #1612: 4 _ 2 _ 5 _ 9 = 19 hard #1626: 4 _ 2 _ 7 _ 3 = 17 hard #1628: 4 _ 2 _ 7 _ 4 = 18 hard #1630: 4 _ 2 _ 7 _ 5 = 19 hard #1632: 4 _ 2 _ 7 _ 6 = 20 hard #1652: 4 _ 2 _ 8 _ 9 = -8 hard #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 #1663: 4 _ 2 _ 9 _ 4 = 14 hard #1664: 4 _ 2 _ 9 _ 5 = 13 hard #1665: 4 _ 2 _ 9 _ 7 = 11 hard #1679: 4 _ 3 _ 2 _ 8 = 14 hard #1717: 4 _ 3 _ 6 _ 9 = 11 hard #1718: 4 _ 3 _ 6 _ 9 = -7 hard #1719: 4 _ 3 _ 6 _ 9 = 18 hard #1729: 4 _ 3 _ 6 _ 9 = 17 hard #1736: 4 _ 3 _ 8 _ 4 = 14 hard #1737: 4 _ 3 _ 8 _ 8 = 13 hard #1740: 4 _ 3 _ 8 _ 6 = 16 hard #1745: 4 _ 3 _ 9 _ 9 = 13 hard #1746: 4 _ 3 _ 9 _ 9 = 11 hard #1748: 4 _ 3 _ 9 _ 1 = 13 hard #1751: 4 _ 3 _ 9 _ 4 = 16 hard #1754: 4 _ 3 _ 9 _ 5 = 17 hard #1756: 4 _ 3 _ 9 _ 7 = 19 hard #1757: 4 _ 3 _ 9 _ 8 = 20 hard #1762: 4 _ 4 _ 2 _ 7 = 18 hard #1773: 4 _ 4 _ 2 _ 9 = 17 hard #1777: 4 _ 4 _ 2 _ 8 = 17 hard #1782: 4 _ 4 _ 3 _ 9 = 16 hard #1785: 4 _ 4 _ 3 _ 9 = -8 hard #1809: 4 _ 4 _ 6 _ 2 = 19 hard #1810: 4 _ 4 _ 6 _ 6 = 17 hard #1815: 4 _ 4 _ 7 _ 2 = 18 hard #1816: 4 _ 4 _ 7 _ 7 = 17 hard #1818: 4 _ 4 _ 7 _ 2 = 15 hard #1822: 4 _ 4 _ 8 _ 4 = 18 hard #1823: 4 _ 4 _ 8 _ 4 = 14 hard #1824: 4 _ 4 _ 8 _ 8 = 15 hard #1838: 4 _ 4 _ 8 _ 9 = 11 hard #1839: 4 _ 4 _ 8 _ 9 = -7 hard #1840: 4 _ 4 _ 8 _ 2 = 17 hard #1841: 4 _ 4 _ 9 _ 3 = 16 hard #1843: 4 _ 4 _ 9 _ 3 = -8 hard #1844: 4 _ 4 _ 9 _ 3 = 19 hard