194847

This is how I solved the first problem in Trebling:
1. First I saw that we were multiplying 1abcde by 3 and the answer ended in 1 so 3xe must be a multiple of 3 and end in 1 so I got 21 (7x3) which means that E=7

2. Then, I carried the 2 (20) and put the 10s digit (e) as 7. Now I know that 3xd=Multiple of 3+2 (2 came from the remainder). I did 7-2=5 so I know that D has to be 5 and the only multiple of 3 that ends with 5 is 15 so I ended up with D=5 and carried the 1.

3. Using the equation: Letterx3+remainder=next letter, I managed to do this for all the other numbers then solved the whole question again and see if I would get the same answer.