Let's call that number x, twice the number will be 2x, sum of it and 5 is, 2x+5. So if this expression is at most 15, it means, it can be only less than 15 and equal to 15. Let's show this as an inequality.
Let's solve.
![x\quad \in \quad \left[ -\infty ,5 \right]](https://tex.z-dn.net/?f=x%5Cquad%20%5Cin%20%5Cquad%20%5Cleft%5B%20-%5Cinfty%20%2C5%20%5Cright%5D%20)
If the number is a natural number. The values it can take is,![x\quad \in \quad \left[ 0,1,2,3,4,5 \right]](https://tex.z-dn.net/?f=x%5Cquad%20%5Cin%20%5Cquad%20%5Cleft%5B%200%2C1%2C2%2C3%2C4%2C5%20%5Cright%5D%20)
Let's solve.
If the number is a natural number. The values it can take is,