1. Add the 3 to the 5 and get 8. Then you can take that
together with the one you didn't use in the addition, which
is the 4, and you can make the two two-digit numbers 48 and 84.
2. Add the 3 to the 4 and get 7. Then you can take that
together with the one you didn't use in the addition, which
is the 5, and you can make the two two-digit numbers 57 and 75.
3. Add the 5 to the 4 and get 9. Then you can take that
together with the one you didn't use in the addition, which
is the 3, and you can make the two two-digit numbers 39 and 93.
Edwin