There have been a number of issues with opening sums online on some of the handheld devices. A number of the children’s devices have not been able to open the application - Sums Online. The best explanation for this is that Sums Online is trying to open in Opera whereas it should be opening in Internet Explorer. To resolve this, open Opera, go to settings and untick use as default browser. Then try opening Sums Online. Hopefully this will work with the devices!