Mrs. Rossi wrote the following clues for a mystery number. It is a 4-digit number. The tens are double the ones. The thousands are double the tens. The sum of the digits is 19.

Answer 1

let the hundreds be X

so the only possible cases are

4X21 and 8X42

to have a sum of 19 X can only be 5

(it would have to be 12 for the first case, not possible)

The number is 8542

Answer 2

4321
1234
1533
1234567890

Answer 3

Mrs rossi wrote the following clue first a mystery number
It is a 3-digit number the tens are double the ones the hundreds are double the tens
The sum of the digital is 14 what is the number