Medium Arithmetic Puzzles

#1390: 3 _ 6 _ 9 _ 7 = 9 medium #1392: 3 _ 6 _ 9 _ 8 = -6 medium #1396: 3 _ 6 _ 9 _ 2 = 9 medium #1404: 3 _ 7 _ 3 _ 2 = 14 medium #1407: 3 _ 7 _ 4 _ 6 = 14 medium #1411: 3 _ 7 _ 6 _ 4 = 14 medium #1422: 3 _ 8 _ 2 _ 4 = 12 medium #1424: 3 _ 8 _ 2 _ 1 = 11 medium #1427: 3 _ 8 _ 2 _ 3 = 9 medium #1428: 3 _ 8 _ 2 _ 4 = 8 medium #1438: 3 _ 8 _ 3 _ 4 = 9 medium #1444: 3 _ 8 _ 3 _ 6 = 12 medium #1452: 3 _ 8 _ 4 _ 5 = -7 medium #1455: 3 _ 8 _ 4 _ 2 = 8 medium #1456: 3 _ 8 _ 4 _ 2 = 12 medium #1459: 3 _ 8 _ 4 _ 5 = 11 medium #1461: 3 _ 8 _ 4 _ 6 = 12 medium #1466: 3 _ 8 _ 4 _ 9 = -3 medium #1469: 3 _ 8 _ 5 _ 4 = -7 medium #1481: 3 _ 8 _ 6 _ 3 = 12 medium #1482: 3 _ 8 _ 6 _ 4 = 8 medium #1484: 3 _ 8 _ 6 _ 5 = 9 medium #1489: 3 _ 8 _ 6 _ 8 = 12 medium #1490: 3 _ 8 _ 6 _ 8 = -4 medium #1492: 3 _ 8 _ 6 _ 9 = -5 medium #1499: 3 _ 9 _ 2 _ 3 = 9 medium #1500: 3 _ 9 _ 2 _ 3 = -3 medium #1501: 3 _ 9 _ 2 _ 6 = 9 medium #1504: 3 _ 9 _ 3 _ 2 = 9 medium #1506: 3 _ 9 _ 3 _ 2 = -3 medium #1510: 3 _ 9 _ 3 _ 3 = -2 medium #1511: 3 _ 9 _ 3 _ 4 = -3 medium #1512: 3 _ 9 _ 3 _ 5 = 6 medium #1513: 3 _ 9 _ 3 _ 6 = 7 medium #1514: 3 _ 9 _ 3 _ 6 = -5 medium #1515: 3 _ 9 _ 3 _ 7 = -6 medium #1516: 3 _ 9 _ 3 _ 8 = 9 medium #1518: 3 _ 9 _ 3 _ 9 = 10 medium #1520: 3 _ 9 _ 4 _ 6 = 9 medium #1522: 3 _ 9 _ 4 _ 6 = -3 medium #1528: 3 _ 9 _ 5 _ 6 = 10 medium #1529: 3 _ 9 _ 6 _ 4 = 9 medium #1531: 3 _ 9 _ 6 _ 4 = -3 medium #1538: 3 _ 9 _ 6 _ 4 = 6 medium #1539: 3 _ 9 _ 6 _ 4 = -2 medium #1541: 3 _ 9 _ 6 _ 5 = 7 medium #1542: 3 _ 9 _ 6 _ 5 = 10 medium #1543: 3 _ 9 _ 6 _ 6 = 8 medium