Since 1 US Dollar is equal to 3.1815 Tunisian Dinars, we could say that n United States Dollars are equal to 3.1815 times n Tunisian Dinars. In other words, we could use the following formula:
Tunisian Dinars = United States Dollars x 3.1815
For example, let's say that we want to convert 2.0 United States Dollars to Tunisian Dinars. Then, we just replace United States Dollars in the abovementioned formula with 2.0:
Tunisian Dinars = 2.0 x 3.1815
That is, 2.0 United States Dollars are equal to 6.363 Tunisian Dinars.