Matchstick Puzzles

#625: Fix 3+4=6 easy #626: Fix 6+2=70 hard #627: Fix 0+9=77 hard #628: Fix 8-3=6 easy #629: Fix 5+8=6 medium #630: Fix 9+5=5 easy #631: Fix 3-7=70 hard #632: Fix 6+2=11 easy #633: Fix 0+7=1 medium #634: Fix 2+4=0 easy #635: Fix 9-3=9 easy #636: Fix 4+5=7 easy #637: Fix 9-7=0 medium #638: Fix 1-6=7 medium #639: Fix 3+3=9 easy #640: Fix 0-3=3 easy #641: Fix 4-2=8 hard #642: Fix 9+6=12 medium #643: Fix 5+6=72 hard #644: Fix 9-4=2 easy #645: Fix 0+5=8 medium #646: Fix 8+2=16 medium #647: Fix 8-3=12 hard #648: Fix 9+3=3 easy #649: Fix 5+3=7 easy #650: Fix 3+6=17 medium #651: Fix 8-3=71 hard #652: Fix 6-8=1 easy #653: Fix 5+9=16 medium #654: Fix 0+8=18 medium #655: Fix 3-7=18 hard #656: Fix 1+1=6 medium #657: Fix 9-8=15 hard #658: Fix 8+7=1 medium #659: Fix 3+2=7 easy #660: Fix 5+0=6 medium #661: Fix 4+1=71 hard #662: Fix 7-7=6 easy #663: Fix 5-6=8 medium #664: Fix 9-4=3 easy #665: Fix 5+9=12 medium #666: Fix 4-1=6 medium #667: Fix 5-6=1 medium #668: Fix 0+6=2 medium #669: Fix 3+4=9 easy #670: Fix 0+8=5 medium #671: Fix 7-9=1 easy #672: Fix 1+4=71 hard