diff --git a/reasoning_gym/arithmetic/basic_arithmetic.py b/reasoning_gym/arithmetic/basic_arithmetic.py
index 677141bf..b0c3dc5d 100644
--- a/reasoning_gym/arithmetic/basic_arithmetic.py
+++ b/reasoning_gym/arithmetic/basic_arithmetic.py
@@ -6,11 +6,12 @@ from typing import Optional, Literal, Any
 @dataclass
 class ArithmeticDatasetConfig:
     """Configuration for arithmetic dataset generation"""
+
     min_terms: int = 2
     max_terms: int = 6
     min_digits: int = 1
     max_digits: int = 4
-    operators: list[str] = ("+" , "-", "*")
+    operators: list[str] = ("+", "-", "*")
     allow_parentheses: bool = True
     allow_negation: bool = True
     seed: Optional[int] = None
@@ -30,22 +31,22 @@ class ArithmeticDatasetConfig:
 
 class ArithmeticDataset:
     """Dataset that generates arithmetic tasks with configurable complexity"""
-    
+
     def __init__(self, config: ArithmeticDatasetConfig):
         self.config = config
         self.config.validate()
         # Generate base seed if none provided
         self.seed = config.seed if config.seed is not None else Random().randint(0, 2**32)
-        
+
     def __len__(self) -> int:
         return self.config.size
-        
+
     def __getitem__(self, idx: int) -> dict[str, Any]:
         """Generate a single arithmetic task
-        
+
         Args:
             idx: Index of the item to generate
-            
+
         Returns:
             dict with keys:
                 - question: str, the formatted arithmetic expression
@@ -54,25 +55,21 @@ class ArithmeticDataset:
         """
         # Create deterministic RNG from base seed and idx
         item_rng = Random(self.seed + idx)
-        
+
         num_terms = item_rng.randint(self.config.min_terms, self.config.max_terms)
         num_digits = item_rng.randint(self.config.min_digits, self.config.max_digits)
-        
+
         if self.config.allow_parentheses:
             expression, result = self._generate_complex_task(item_rng, num_terms, num_digits)
         else:
             expression, result = self._generate_simple_task(item_rng, num_terms, num_digits)
-            
+
         question = self._format_question(expression)
-            
+
         return {
             "question": question,
             "answer": str(result),
-            "metadata": {
-                "num_terms": num_terms,
-                "num_digits": num_digits,
-                "expression": expression
-            }
+            "metadata": {"num_terms": num_terms, "num_digits": num_digits, "expression": expression},
         }
 
     def _generate_complex_task(self, rng: Random, num_terms: int, num_digits: int) -> tuple[str, int]:
@@ -142,13 +139,11 @@ class ArithmeticDataset:
         expression = " ".join(expression_parts)
         return expression, result
 
-
-
     def __iter__(self):
         """Make the dataset iterable"""
         self._current_idx = 0
         return self
-        
+
     def __next__(self):
         """Get next item in iteration"""
         if self._current_idx >= self.config.size:
@@ -162,12 +157,7 @@ class ArithmeticDataset:
         if self.config.format_style == "simple":
             return f"{expression} ="
         else:
-            templates = [
-                "What is {0}?",
-                "Calculate {0}",
-                "Solve {0}",
-                "Evaluate the expression: {0}"
-            ]
+            templates = ["What is {0}?", "Calculate {0}", "Solve {0}", "Evaluate the expression: {0}"]
             # Use deterministic RNG for template selection
             template_rng = Random(self.seed)
             return template_rng.choice(templates).format(expression)