Deber Farias 1A

http://office.microsoft.com/es-hn/excel-help/funcion-sumar-si-conjunto-HA010047504.aspx

http://office.microsoft.com/es-ar/excel-help/suma-HP005209290.aspx

http://office.microsoft.com/es-hn/excel-help/truncar-HP005209324.aspx