$$2\frac{1}{2}/6$$
The general method
Turn the mixed numerals into an improper fraction using this formula (can you see why it's true):
$$a\frac{b}{c}=\frac{ac+b}{c}$$
We get:
$$2\frac{1}{2}=\frac{2*2+1}{2}=\frac{5}{2}$$
Thus the whole expression gets:
$$\frac{5}{2}/6=\frac{5}{2*6}=\frac{5}{12}$$
The efficient method
Realise that 2 1/2 =2.5
We get: 2.5/6 = 5/12
$$2\frac{1}{2}/6$$
The general method
Turn the mixed numerals into an improper fraction using this formula (can you see why it's true):
$$a\frac{b}{c}=\frac{ac+b}{c}$$
We get:
$$2\frac{1}{2}=\frac{2*2+1}{2}=\frac{5}{2}$$
Thus the whole expression gets:
$$\frac{5}{2}/6=\frac{5}{2*6}=\frac{5}{12}$$
The efficient method
Realise that 2 1/2 =2.5
We get: 2.5/6 = 5/12