1990/1/1: 010190 = 010:190 = integer ratio of 1 to 19
1990/1/2: 010290 = 010:290 = integer ratio of 1 to 29
1990/1/3: 010390 = 010:390 = integer ratio of 1 to 39
1990/1/4: 010490 = 010:490 = integer ratio of 1 to 49
1990/1/5: 010590 = 010:590 = integer ratio of 1 to 59
1990/1/5: 1590 = 15:90 = integer ratio of 1 to 6
1990/1/5: 9015 = 90:15 = integer ratio of 6 to 1
1990/1/6: 010690 = 010:690 = integer ratio of 1 to 69
1990/1/6: 06190 = 180 deg rotationally symmetric
1990/1/6: 90106 = 180 deg rotationally symmetric
1990/1/7: 010790 = 010:790 = integer ratio of 1 to 79
1990/1/8: 010890 = 010:890 = integer ratio of 1 to 89
1990/1/8: 1890 = 18:90 = integer ratio of 1 to 5
1990/1/8: 9018 = 90:18 = integer ratio of 5 to 1
1990/1/9: 010990 = 010:990 = integer ratio of 1 to 99
1990/1/9: 09190 = palindrome
1990/1/9: 90109 = palindrome
1990/1/19: 011990 = 011:990 = integer ratio of 1 to 90
1990/1/19: 190190 = cyclic permutation symmetric
1990/2/1: 010290 = 010:290 = integer ratio of 1 to 29
1990/2/9: 09290 = palindrome
1990/2/9: 90209 = palindrome
1990/2/25: 900225 = 900:225 = integer ratio of 4 to 1
1990/3/1: 010390 = 010:390 = integer ratio of 1 to 39
1990/3/3: 030390 = 030:390 = integer ratio of 1 to 13
1990/3/6: 030690 = 030:690 = integer ratio of 1 to 23
1990/3/9: 030990 = 030:990 = integer ratio of 1 to 33
1990/3/9: 09390 = palindrome
1990/3/9: 90309 = palindrome
1990/3/13: 130390 = 130:390 = integer ratio of 1 to 3
1990/4/1: 010490 = 010:490 = integer ratio of 1 to 49
1990/4/5: 4590 = 45:90 = integer ratio of 1 to 2
1990/4/5: 9045 = 90:45 = integer ratio of 2 to 1
1990/4/7: 070490 = 070:490 = integer ratio of 1 to 7
1990/4/9: 09490 = palindrome
1990/4/9: 90409 = palindrome
1990/5/1: 010590 = 010:590 = integer ratio of 1 to 59
1990/5/1: 1590 = 15:90 = integer ratio of 1 to 6
1990/5/4: 4590 = 45:90 = integer ratio of 1 to 2
1990/5/9: 09590 = palindrome
1990/5/9: 90509 = palindrome
1990/6/1: 010690 = 010:690 = integer ratio of 1 to 69
1990/6/1: 06190 = 180 deg rotationally symmetric
1990/6/3: 030690 = 030:690 = integer ratio of 1 to 23
1990/6/6: 0661990 = 180 deg rotationally symmetric
1990/6/9: 09690 = palindrome
1990/6/9: 90609 = palindrome
1990/6/11: 061190 = 180 deg rotationally symmetric
1990/6/23: 230690 = 230:690 = integer ratio of 1 to 3
1990/7/1: 010790 = 010:790 = integer ratio of 1 to 79
1990/7/4: 070490 = 070:490 = integer ratio of 1 to 7
1990/7/9: 09790 = palindrome
1990/7/9: 90709 = palindrome
1990/8/1: 010890 = 010:890 = integer ratio of 1 to 89
1990/8/1: 1890 = 18:90 = integer ratio of 1 to 5
1990/8/9: 09890 = palindrome
1990/8/9: 90809 = palindrome
1990/9/1: 010990 = 010:990 = integer ratio of 1 to 99
1990/9/1: 09190 = palindrome
1990/9/2: 09290 = palindrome
1990/9/3: 030990 = 030:990 = integer ratio of 1 to 33
1990/9/3: 09390 = palindrome
1990/9/4: 09490 = palindrome
1990/9/5: 09590 = palindrome
1990/9/6: 09690 = palindrome
1990/9/7: 09790 = palindrome
1990/9/8: 09890 = palindrome
1990/9/9: 090990 = 090:990 = integer ratio of 1 to 11
1990/9/9: 0991990 = palindrome
1990/9/9: 09990 = palindrome
1990/9/9: 90909 = palindrome
1990/9/11: 091190 = palindrome
1990/9/11: 110990 = 110:990 = integer ratio of 1 to 9
1990/9/22: 092290 = palindrome
1990/10/1: 901001 = 901:001 = integer ratio of 901 to 1
1990/10/6: 90106 = 180 deg rotationally symmetric
1990/10/9: 90109 = palindrome
1990/10/10: 101090 = 101:090 = each is palindrome
1990/10/11: 111090 = 111:090 = each is palindrome
1990/10/12: 121090 = 121:090 = each is palindrome
1990/10/13: 131090 = 131:090 = each is palindrome
1990/10/14: 141090 = 141:090 = each is palindrome
1990/10/15: 151090 = 151:090 = each is palindrome
1990/10/16: 161090 = 161:090 = each is palindrome
1990/10/17: 171090 = 171:090 = each is palindrome
1990/10/17: 901017 = 901:017 = integer ratio of 53 to 1
1990/10/18: 181090 = 181:090 = each is palindrome
1990/10/19: 191090 = 191:090 = each is palindrome
1990/10/30: 103090 = 10:30:90 = geometric series of ratio 3
1990/11/6: 061190 = 180 deg rotationally symmetric
1990/11/6: 901106 = 180 deg rotationally symmetric
1990/11/9: 091190 = palindrome
1990/11/9: 110990 = 110:990 = integer ratio of 1 to 9
1990/11/9: 901109 = palindrome
1990/11/10: 111090 = 111:090 = each is palindrome
1990/12/10: 121090 = 121:090 = each is palindrome