− 60 ∘ ⋅ π 180 ∘ = − ( 2 ⋅ 2 ⋅ 3 ⋅ 5 ) 1 ⋅ π 2 ⋅ 2 ⋅ 5 ⋅ 3 ⋅ 3 = − π 3 {\displaystyle -60^{\circ }\cdot {\frac {\pi }{180^{\circ }}}={\frac {-({\cancel {2}}\cdot {\cancel {2}}\cdot {\cancel {3}}\cdot {\cancel {5}})}{1}}\cdot {\frac {\pi }{{\cancel {2}}\cdot {\cancel {2}}\cdot {\cancel {5}}\cdot {\cancel {3}}\cdot 3}}=-{\frac {\pi }{3}}}
