var style = new GC.Spread.Sheets.Style();
style.backColor = "red";
var ranges = [new GC.Spread.Sheets.Range(0, 0, 2, 1)];
activeSheet.conditionalFormats.addFormulaRule("=A1=B1+C1", style, ranges);
activeSheet.setValue(0, 0, 2,3);
activeSheet.setValue(0, 1, 1,3);
activeSheet.setValue(0, 2,1,3);
activeSheet.setValue(1, 0, 1,3);