Since 31 is a Prime number, you would simply make two branches: one for 1, and one for 31.
31 is prime. No tree.
1 and 31
155 5, 31
no
The factor tree is as follows: 114 57,2 19,3,2
124 2 * 62 2 * 2 * 31
No.
4342, 2172, 7, 31Note: 31 is a prime number
310 310=31x5x2 31 10 2 5
740 /\ 10 74 /\ /\ 5 5 2 31
yes
991 is already prime. No tree is required.