Hard Arithmetic Puzzles

#3078: 6 _ 8 _ 2 _ 3 = 18 hard #3081: 6 _ 8 _ 2 _ 5 = 19 hard #3082: 6 _ 8 _ 2 _ 8 = 16 hard #3083: 6 _ 8 _ 2 _ 9 = 15 hard #3088: 6 _ 8 _ 3 _ 9 = 16 hard #3089: 6 _ 8 _ 3 _ 1 = 15 hard #3090: 6 _ 8 _ 3 _ 2 = 14 hard #3091: 6 _ 8 _ 3 _ 3 = 19 hard #3092: 6 _ 8 _ 3 _ 4 = 20 hard #3101: 6 _ 8 _ 4 _ 5 = 16 hard #3105: 6 _ 8 _ 4 _ 1 = 13 hard #3106: 6 _ 8 _ 4 _ 2 = 14 hard #3108: 6 _ 8 _ 4 _ 4 = 16 hard #3110: 6 _ 8 _ 4 _ 5 = 17 hard #3112: 6 _ 8 _ 4 _ 7 = 19 hard #3114: 6 _ 8 _ 4 _ 8 = 20 hard #3128: 6 _ 8 _ 5 _ 4 = 16 hard #3131: 6 _ 8 _ 6 _ 9 = 18 hard #3134: 6 _ 8 _ 6 _ 2 = 16 hard #3139: 6 _ 8 _ 9 _ 6 = 18 hard #3140: 6 _ 8 _ 9 _ 3 = 16 hard #3141: 6 _ 9 _ 2 _ 3 = 12 hard #3142: 6 _ 9 _ 2 _ 8 = 19 hard #3143: 6 _ 9 _ 2 _ 9 = 18 hard #3148: 6 _ 9 _ 3 _ 2 = 12 hard #3149: 6 _ 9 _ 3 _ 4 = 18 hard #3151: 6 _ 9 _ 3 _ 5 = -9 hard #3160: 6 _ 9 _ 3 _ 7 = 14 hard #3162: 6 _ 9 _ 3 _ 8 = 16 hard #3163: 6 _ 9 _ 3 _ 9 = 11 hard #3164: 6 _ 9 _ 3 _ 9 = -7 hard #3165: 6 _ 9 _ 4 _ 3 = 18 hard #3166: 6 _ 9 _ 4 _ 6 = 12 hard #3168: 6 _ 9 _ 4 _ 6 = 16 hard #3170: 6 _ 9 _ 5 _ 3 = -9 hard #3172: 6 _ 9 _ 5 _ 6 = 20 hard #3173: 6 _ 9 _ 6 _ 4 = 12 hard #3174: 6 _ 9 _ 6 _ 8 = 18 hard #3183: 6 _ 9 _ 6 _ 4 = 16 hard #3187: 6 _ 9 _ 6 _ 5 = 20 hard #3189: 6 _ 9 _ 6 _ 7 = 11 hard #3191: 6 _ 9 _ 6 _ 8 = 12 hard #3193: 6 _ 9 _ 6 _ 9 = 13 hard #3195: 6 _ 9 _ 8 _ 6 = 18 hard #3197: 6 _ 9 _ 8 _ 3 = 16 hard #3204: 7 _ 2 _ 3 _ 9 = 13 hard #3210: 7 _ 2 _ 4 _ 4 = 15 hard #3212: 7 _ 2 _ 4 _ 4 = 18 hard