Hard Arithmetic Puzzles

#3473: 7 _ 8 _ 2 _ 8 = 20 hard #3474: 7 _ 8 _ 2 _ 9 = 19 hard #3475: 7 _ 8 _ 3 _ 2 = 19 hard #3476: 7 _ 8 _ 3 _ 4 = 13 hard #3481: 7 _ 8 _ 3 _ 6 = -9 hard #3482: 7 _ 8 _ 4 _ 3 = 13 hard #3483: 7 _ 8 _ 4 _ 5 = 17 hard #3484: 7 _ 8 _ 4 _ 6 = 19 hard #3489: 7 _ 8 _ 4 _ 8 = -9 hard #3490: 7 _ 8 _ 4 _ 1 = 15 hard #3491: 7 _ 8 _ 4 _ 1 = 13 hard #3492: 7 _ 8 _ 4 _ 2 = 16 hard #3494: 7 _ 8 _ 4 _ 3 = 17 hard #3495: 7 _ 8 _ 4 _ 4 = 18 hard #3498: 7 _ 8 _ 4 _ 6 = 20 hard #3503: 7 _ 8 _ 5 _ 4 = 17 hard #3505: 7 _ 8 _ 6 _ 4 = 19 hard #3507: 7 _ 8 _ 6 _ 9 = 19 hard #3508: 7 _ 8 _ 6 _ 3 = -9 hard #3513: 7 _ 8 _ 7 _ 2 = 16 hard #3514: 7 _ 8 _ 8 _ 4 = -9 hard #3515: 7 _ 8 _ 9 _ 6 = 19 hard #3517: 7 _ 9 _ 2 _ 3 = 13 hard #3519: 7 _ 9 _ 3 _ 2 = 13 hard #3520: 7 _ 9 _ 3 _ 4 = 19 hard #3523: 7 _ 9 _ 3 _ 5 = -8 hard #3524: 7 _ 9 _ 3 _ 2 = 19 hard #3525: 7 _ 9 _ 3 _ 3 = 18 hard #3526: 7 _ 9 _ 3 _ 5 = 16 hard #3527: 7 _ 9 _ 3 _ 6 = 15 hard #3528: 7 _ 9 _ 3 _ 7 = 14 hard #3529: 7 _ 9 _ 3 _ 8 = 13 hard #3530: 7 _ 9 _ 3 _ 9 = 12 hard #3531: 7 _ 9 _ 3 _ 6 = 14 hard #3532: 7 _ 9 _ 4 _ 3 = 19 hard #3533: 7 _ 9 _ 4 _ 6 = 13 hard #3536: 7 _ 9 _ 5 _ 3 = -8 hard #3537: 7 _ 9 _ 6 _ 4 = 13 hard #3538: 7 _ 9 _ 6 _ 8 = 19 hard #3541: 7 _ 9 _ 7 _ 2 = 18 hard #3543: 7 _ 9 _ 8 _ 6 = 19 hard #3546: 8 _ 1 _ 3 _ 9 = 11 hard #3551: 8 _ 2 _ 2 _ 2 = 17 hard #3552: 8 _ 2 _ 2 _ 2 = 15 hard #3553: 8 _ 2 _ 2 _ 6 = 16 hard #3554: 8 _ 2 _ 2 _ 7 = 18 hard #3561: 8 _ 2 _ 3 _ 9 = 14 hard #3565: 8 _ 2 _ 3 _ 3 = 13 hard