diff --git a/README.md b/README.md
index e6fbcd8..3093773 100644
--- a/README.md
+++ b/README.md
@@ -5211,7 +5211,7 @@ Map::from( [['p' => 30], ['p' => 50], ['p' => 10]] )->sum( 'p' );
 Map::from( [['i' => ['p' => 30]], ['i' => ['p' => 50]]] )->sum( 'i/p' );
 // 80
 
-Map::from( [30, 50, 10] )->sum( fn( $val, $key ) => $val < 50 ? $val : 0 );
+Map::from( [30, 50, 10] )->sum( fn( $val, $key ) => $val < 50 );
 // 40
 ```
 
diff --git a/tests/MapTest.php b/tests/MapTest.php
index 21fd452..a19fc66 100644
--- a/tests/MapTest.php
+++ b/tests/MapTest.php
@@ -3122,8 +3122,8 @@ public function testSum()
 
 	public function testSumClosure()
 	{
-		$this->assertSame( 40.0, Map::from( [30, 50, 10] )->sum( function( $val ) { return $val < 50 ? $val : 0; } ) );
-		$this->assertSame( 60.0, Map::from( [30, 50, 10] )->sum( function( $val, $key ) { return $key > 0 ? $val : 0; } ) );
+		$this->assertSame( 40.0, Map::from( [30, 50, 10] )->sum( function( $val ) { return $val < 50; } ) );
+		$this->assertSame( 60.0, Map::from( [30, 50, 10] )->sum( function( $val, $key ) { return $key > 0; } ) );
 	}