?
# before and after
between..
10 more
10 less
100

50 is one more than...

49

100

23

22, 24

100

28, 30

29

100

17

27

100

21

11

200

61 is one less than..

62

200

56

55, 57

200

62, 64

63

200

23

33

200

34

24

300

45 is one less than...

46

300

65

64, 66

300

80, 82

81

300

60

70

300

65

55

400

21 is one more than...

20

400

75

74, 76

400

97, 99

98

400

82

92

400

89

79

500

99 is one less than 

100

500

99

98, 100

500

79, 81

80

500

90

100

500

99

89