Weird Calculator Puzzles

You own a weird calculator with only 4 buttons, which perform the following 4 operations:
  . Your challenge is to add 1 to the numbers below by only pushing these buttons. For example, 2 → 3 with 2 buttons has solution:  .


#1: 5 → 6 with 2 buttons #19: 87 → 88 with 5 buttons
#2: 9 → 10 with 2 buttons #20: 89 → 90 with 5 buttons
#3: 18 → 19 with 2 buttons #21: 99 → 100 with 5 buttons
 
#4: 54 → 55 with 3 buttons #22: 35 → 36 with 6 buttons
  #23: 50 → 51 with 6 buttons
#5: 24 → 25 with 4 buttons #24: 70 → 71 with 6 buttons
#6: 31 → 32 with 4 buttons #25: 73 → 74 with 6 buttons
#7: 34 → 35 with 4 buttons #26: 83 → 84 with 6 buttons
#8: 44 → 45 with 4 buttons #27: 90 → 91 with 6 buttons
#9: 57 → 58 with 4 buttons #28: 96 → 97 with 6 buttons
   
#10: 7 → 8 with 5 buttons #29: 46 → 47 with 7 buttons
#11: 20 → 21 with 5 buttons #30: 48 → 49 with 7 buttons
#12: 23 → 24 with 5 buttons #31: 49 → 50 with 7 buttons
#13: 30 → 31 with 5 buttons #32: 58 → 59 with 7 buttons
#14: 32 → 33 with 5 buttons #33: 85 → 86 with 7 buttons
#15: 52 → 53 with 5 buttons #34: 94 → 95 with 7 buttons
#16: 74 → 75 with 5 buttons #35: 95 → 96 with 7 buttons
#17: 75 → 76 with 5 buttons  
#18: 82 → 83 with 5 buttons #36: 88 → 89 with 8 buttons

The answers are here.