1-2 times the square root of ten divided by 4 + the square root of ten
$$\\1-2\times\frac{\sqrt{10}}{4}+\sqrt{10}\\\\ =1-\frac{\sqrt{10}}{2}+\frac{2\sqrt{10}}{2}\\\\ =1+\frac{\sqrt{10}}{2}\\\\ =\frac{2+\sqrt{10}}{2}\\\\$$