Hard Matchstick Puzzles

#169: Fix 4-8=72 hard #175: Fix 3-3=8 hard #176: Fix 8+1=75 hard #178: Fix 8+0=76 hard #183: Fix 5-8=11 hard #184: Fix 9+1=6 hard #197: Fix 9+2=70 hard #198: Fix 0+4=72 hard #199: Fix 8-0=0 hard #206: Fix 8-4=10 hard #211: Fix 9+5=73 hard #213: Fix 9-7=10 hard #217: Fix 8-1=1 hard #222: Fix 2-8=11 hard #223: Fix 4-5=8 hard #225: Fix 8-1=10 hard #226: Fix 4-7=17 hard #233: Fix 4+5=70 hard #234: Fix 0+0=8 hard #235: Fix 4+6=72 hard #240: Fix 8-7=13 hard #241: Fix 9+5=75 hard #243: Fix 6-8=6 hard #244: Fix 5+0=73 hard #245: Fix 2-9=71 hard #246: Fix 8+8=75 hard #249: Fix 5+1=72 hard #253: Fix 8+9=0 hard #257: Fix 9+9=1 hard #258: Fix 9+2=1 hard #261: Fix 9+0=8 hard #265: Fix 6-7=73 hard #274: Fix 0+8=76 hard #279: Fix 2+6=70 hard #280: Fix 8-5=11 hard #283: Fix 7-9=10 hard #286: Fix 3+9=71 hard #291: Fix 2-7=8 hard #297: Fix 5+9=73 hard #303: Fix 8+0=9 hard #307: Fix 8-1=8 hard #308: Fix 3-8=71 hard #309: Fix 4-9=73 hard #311: Fix 6+0=74 hard #312: Fix 0-8=6 hard #313: Fix 9-3=72 hard #317: Fix 8-9=15 hard #321: Fix 8+6=0 hard