# Simple Calculations With .NET

For simple math expressions calculation I use the DataTable class. Very simple and we already have it! Also, we can use some SQL expressions (list at http://msdn.microsoft.com/en-us/library/system.data.datacolumn.expression.aspx):

`   1: var table = new DataTable();`
`   2: table.Columns.Add("A", typeof(int));`
`   3: table.Columns.Add("B", typeof(int));`
`   4:  `
`   5: var c = new DataColumn("C"){ Expression = "[A] + [B]" };`
`   6: table.Columns.Add(c);`
`   7:  `
`   8: var d = new DataColumn("D"){ Expression = "ISNULL([A], [B])" };`
`   9: table.Columns.Add(d);`
`  10:  `
`  11: table.Rows.Add(1, 2);`
`  12:  `
`  13: var resultc = table.Rows["C"];    //3`
`  14: var resultd = table.Rows["D"];    //1`

It can also be used for aggregations:

`   1: var sum = table.Compute("SUM([A])", String.Empty);`
`   2: var avg = table.Compute("AVG([B])", String.Empty);`

For the list of supported expressions, see http://msdn.microsoft.com/en-us/library/system.data.datatable.compute.aspx.

Easy, and no need for external libraries! 