diff --git a/src/main/java/org/ssssssss/script/functions/StreamExtension.java b/src/main/java/org/ssssssss/script/functions/StreamExtension.java
index 3750ad20d7779f2835f3a40ab39441d5c8ed1156..f0010f92824ea5d8051a02b1ef8c0b4ce9b2b477 100644
--- a/src/main/java/org/ssssssss/script/functions/StreamExtension.java
+++ b/src/main/java/org/ssssssss/script/functions/StreamExtension.java
@@ -7,6 +7,7 @@ import org.ssssssss.script.parsing.ast.literal.BooleanLiteral;
 import org.ssssssss.script.reflection.JavaReflection;
 
 import java.lang.reflect.Array;
+import java.math.BigDecimal;
 import java.util.*;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -386,8 +387,8 @@ public class StreamExtension {
 	public Number sum(Object target) {
 		return arrayLikeToList(target).stream()
 				.filter(value -> value instanceof Number)
-				.mapToDouble(value -> ((Number) value).doubleValue())
-				.sum();
+				.map(x -> new BigDecimal(String.valueOf(x)))
+				.reduce(BigDecimal.ZERO, BigDecimal::add);
 	}
 
 	/**