# BigInteger.Multiply(BigInteger, BigInteger) Method

## Definition

Returns the product of two BigInteger values.

``````public:
static System::Numerics::BigInteger Multiply(System::Numerics::BigInteger left, System::Numerics::BigInteger right);``````
``public static System.Numerics.BigInteger Multiply (System.Numerics.BigInteger left, System.Numerics.BigInteger right);``
``static member Multiply : System.Numerics.BigInteger * System.Numerics.BigInteger -> System.Numerics.BigInteger``
``Public Shared Function Multiply (left As BigInteger, right As BigInteger) As BigInteger``

#### Parameters

left
BigInteger

The first number to multiply.

right
BigInteger

The second number to multiply.

#### Returns

BigInteger

The product of the `left` and `right` parameters.

## Examples

The following example tries to perform multiplication with two long integers. Because the result exceeds the range of a long integer, an OverflowException is thrown, and the Multiply method is called to handle the multiplication. Note that C# requires that you use either the `checked` keyword (as in this example) or the `/checked+` compiler option to make sure an exception is thrown on a numeric overflow.

``````long number1 = 1234567890;
long number2 = 9876543210;
try
{
long product;
product = checked(number1 * number2);
}
catch (OverflowException)
{
BigInteger product;
product = BigInteger.Multiply(number1, number2);
Console.WriteLine(product.ToString());
}
``````
``````Dim number1 As Long = 1234567890
Dim number2 As Long = 9876543210
Try
Dim product As Long
product = number1 * number2
Console.WriteLine(product.ToString("N0"))
Catch e As OverflowException
Dim product As BigInteger
product = BigInteger.Multiply(number1, number2)
Console.WriteLine(product.ToString)
End Try
``````

## Remarks

The Multiply method is implemented for languages that do not support operator overloading. Its behavior is identical to multiplication using the multiplication operator. In addition, the Multiply method is a useful substitute for the multiplication operator when instantiating a BigInteger variable by assigning it a product that results from multiplication, as shown in the following example.

``````// The statement
//    BigInteger number = Int64.MaxValue * 3;
// produces compiler error CS0220: The operation overflows at compile time in checked mode.
// The alternative:
BigInteger number = BigInteger.Multiply(Int64.MaxValue, 3);
``````
``````' The statement
'    Dim number As BigInteger = Int64.MaxValue * 3
' produces compiler error BC30439: Constant expression not representable in type 'Long'.
' The alternative:
Dim number As BigInteger = BigInteger.Multiply(Int64.MaxValue, 3)
``````

If necessary, this method automatically performs implicit conversion of other integral types to BigInteger objects. This is illustrated in the example in the next section, where the Multiply method is passed two Int64 values.