VTMO 2026 - Grade 5 - Semifinal - SET 7 - Self-study Question 1

We can write 8 as a product of natural numbers whose sum is also 8. For example, $8=1\times1\times2\times4$ and $8=1+1+2+4$. How many ways can 20 be written as a product of natural numbers whose sum is also 20?

Practice convention: use at least two factors. Rearranging the same factors does not make a new way.