I came out with this C# algorithm to solve this problem, I did a research and found a better solution named Russian Peasant please research for that, I this code I will do by sum number a and accumulate the sum b times.

```
/// <summary>
/// Multiplies withou using Multiply
/// </summary>
/// <param name="a">first number</param>
/// <param name="b">second number</param>
/// <returns>multiply</returns>
private static int Multiply(int a, int b)
{
int total = 0; // sum
for (int i = 1; i <= b; i++)
{
total += a; // sum number a as many timeas as b
}
return total;
}
```

As I said is not the most efficient maybe research on what I wold you.

Thanks

Mario