The phrase a number means an arbitrary variable, let's call it x.
2 times a number means we multiply 2 by x:
2x
That number plus 5 means we add 5 to the number x
x + 5
The phrase equals means we set both expressions equal to each other
2x = x + 5 <-- This is our algebraic expression
If you want to take this further and solve this equation for x, type this expression in the search engine and we get:
x = 5
ncG1vJloZrCvp2O6osDHnJylnZKntrXFjZympmeTpLquwc2iq7JnpJ2%2Fpq3DrGZrZaSeuqa%2FjJpkp62dl7KzecSqrJqko2LBqa3TZqWupZKav268y66qZm1eZoR5hY4%3D