### Sage refuses to evaluate summations...

I'm trying to define a ~~function g(x)=sum(frac(j~~*p/q),j,0,x) **function*

* *```
g(x) = sum(frac(j*p/q), j, 0, x)
```

*where *~~p,q ~~`p`

, `q`

are pre-defined constants (say ~~(p,q)=(33,21)). ~~`(p, q)=(33, 21)`

).
Sage did not give any errors, but when I type ~~g(10), ~~`g(10)`

,
I would get output symbolic expression ~~sum(frac(11/7~~j), `sum(frac(11/7*j), `

`j, 0, `~~10), ~~10)

,
which is different from the expected value ~~31/7.~~`31/7`

.

How do I fix this?