```calc
x/2 + x/3 -> ?
diff(x*sin(x), x) -> ?
int(x*sin(x), x) -> ?
```

```calc
(x + 1)^2 -> expand -> ?
x^2 - 1 -> factor -> ?
x^2 - 4 -> solve(x) -> ?
a*x^2 + b*x + c -> solve(x) -> ?
sin(x) -> series(x, 6) -> ?
π -> float(4) -> ?
```