diff --git a/tessellations/sample/README.md b/tessellations/sample/README.md
index de29569c..3cca7b50 100644
--- a/tessellations/sample/README.md
+++ b/tessellations/sample/README.md
@@ -56,7 +56,7 @@ As mentioned above, all the numerical values can be provided as formulas. Formul
 
 You can use the constants: `pi`, `deg`, `e`, `i`, `inf` (infinity). You can also declare new constants as in `let(tau=2*pi)`.
 
-You can use the standard math functions `sin`, `cos`, `tan`, `sinh`, `cosh`, `tanh`, `asin`, `acos`, `atan`, `asinh`, `acosh`, `atanh`, `exp`, `sqrt`, `log` (natural logarithm), `tan`,
+You can use the standard math operators `+`, `-`, `*` (multiplication), `/` (division), `^` (exponentation), and math functions `sin`, `cos`, `tan`, `sinh`, `cosh`, `tanh`, `asin`, `acos`, `atan`, `asinh`, `acosh`, `atanh`, `exp`, `sqrt`, `log` (natural logarithm), `tan`,
 `re` (real part), `im` (imaginary part), `conj` (conjugation), `floor`, `frac` (fractional part), `min`, `max`. 
 
 Programming-style functions: `ifz(x,a,b)` (a if x=0, b otherwise), `ifp(x,a,b)` (a if x is positive, b otherwise), `test(x)` (returns x but also displays x while reading the file),