diff --git a/units.py b/units.py
index 933a0ea..bc92fb3 100644
--- a/units.py
+++ b/units.py
@@ -43,21 +43,21 @@ def unit_str(unit, base=None, prefix="", format=" [{unit}]"):
         return ""
     elif base is not None:
         coeff = unit.express(base)
-        return unit_str(base, prefix=convert_exp(coeff) + " ")
+        return unit_str(base, prefix=convert_exp(coeff)+" ")
     elif len(unit.latex) > 0:
         if "." in unit.latex or "^" in unit.latex:
             base_str = ".".join(map(parse_exp_unit, unit.name.split(".")))
-            u_str = r"${}{}$".format(prefix, base_str)
+            u_str = r"{}${}$".format(prefix, base_str)
         else:
-            u_str = r"${}{}$".format(prefix, unit.latex.replace("text", "math"))
+            u_str = r"{}${}$".format(prefix, unit.latex.replace("text", "math"))
     elif len(unit.name) > 0:
         base_str = ".".join(map(parse_exp_unit, unit.name.split(".")))
-        u_str = r"${}{}$".format(prefix, base_str)
+        u_str = r"{}${}$".format(prefix, base_str)
     else:
         base_str = ".".join(
             map(parse_exp_unit, unit._decompose_base_units().split("."))
         )
-        u_str = r"${}{} {}$".format(prefix, unit.coeff, base_str)
+        u_str = r"{}${} {}$".format(prefix, unit.coeff, base_str)
     return format.format(unit=u_str)