Update MathBuilder.java

Author: sadiul-hakim

src/main/java/com/thealgorithms/maths/MathBuilder.java

@@ -331,7 +331,7 @@ public Builder format(String format) {
 
         public Builder format(int decimalPlace) {
             String pattern = "."
-                 + "#".repeat(decimalPlace);
+                + "#".repeat(decimalPlace);
             DecimalFormat formater = new DecimalFormat(pattern);
             String num = formater.format(number);
             number = Double.parseDouble(num);