There are many ways.
One such is 21, 30, 45, 69, 78
Chat with our AI personalities
7, 28, 49, 63, 105 is the series of multiples of 7 using 0-9 only once.
7, 42, 63, 98, 105
99876543210
1, 9, and 81 are the only multiples of 81
Not all multiples of 40 are multiples of 80. Only the even multiples of 40 are also multiples of 80. The odd multiples, e.g. 40, 120, 200, 280, and 360, are not multiples of 80.