Hard Arithmetic Puzzles

#3690: 8 _ 3 _ 5 _ 6 = 20 hard #3696: 8 _ 3 _ 6 _ 9 = 16 hard #3702: 8 _ 3 _ 6 _ 4 = 16 hard #3705: 8 _ 3 _ 6 _ 5 = 20 hard #3708: 8 _ 3 _ 6 _ 9 = 13 hard #3710: 8 _ 3 _ 6 _ 1 = 15 hard #3711: 8 _ 3 _ 6 _ 2 = 18 hard #3712: 8 _ 3 _ 6 _ 3 = 19 hard #3713: 8 _ 3 _ 6 _ 4 = 20 hard #3722: 8 _ 3 _ 8 _ 4 = 14 hard #3729: 8 _ 3 _ 8 _ 6 = 18 hard #3736: 8 _ 3 _ 9 _ 6 = 16 hard #3737: 8 _ 3 _ 9 _ 4 = 20 hard #3738: 8 _ 3 _ 9 _ 6 = 18 hard #3740: 8 _ 3 _ 9 _ 7 = 17 hard #3741: 8 _ 3 _ 9 _ 8 = 16 hard #3743: 8 _ 3 _ 9 _ 9 = 15 hard #3744: 8 _ 4 _ 2 _ 3 = 14 hard #3745: 8 _ 4 _ 2 _ 5 = 18 hard #3751: 8 _ 4 _ 2 _ 6 = 14 hard #3752: 8 _ 4 _ 2 _ 7 = 16 hard #3753: 8 _ 4 _ 2 _ 9 = 20 hard #3759: 8 _ 4 _ 2 _ 5 = 20 hard #3760: 8 _ 4 _ 3 _ 2 = 14 hard #3764: 8 _ 4 _ 3 _ 4 = 14 hard #3765: 8 _ 4 _ 3 _ 6 = 20 hard #3775: 8 _ 4 _ 3 _ 8 = 14 hard #3777: 8 _ 4 _ 3 _ 9 = 15 hard #3781: 8 _ 4 _ 4 _ 3 = 14 hard #3782: 8 _ 4 _ 4 _ 4 = 18 hard #3785: 8 _ 4 _ 5 _ 2 = 18 hard #3790: 8 _ 4 _ 5 _ 2 = 20 hard #3791: 8 _ 4 _ 5 _ 3 = 13 hard #3793: 8 _ 4 _ 5 _ 4 = 14 hard #3795: 8 _ 4 _ 5 _ 5 = 15 hard #3796: 8 _ 4 _ 5 _ 6 = 16 hard #3798: 8 _ 4 _ 5 _ 7 = 17 hard #3800: 8 _ 4 _ 5 _ 8 = 18 hard #3804: 8 _ 4 _ 6 _ 9 = 14 hard #3807: 8 _ 4 _ 6 _ 3 = 20 hard #3808: 8 _ 4 _ 6 _ 1 = 13 hard #3809: 8 _ 4 _ 6 _ 4 = 16 hard #3811: 8 _ 4 _ 6 _ 5 = 17 hard #3813: 8 _ 4 _ 6 _ 6 = 18 hard #3815: 8 _ 4 _ 6 _ 8 = 20 hard #3817: 8 _ 4 _ 7 _ 1 = 15 hard #3818: 8 _ 4 _ 7 _ 1 = 13 hard #3820: 8 _ 4 _ 7 _ 3 = 17 hard