To simplify this expression, we need to use the trigonometric identity:

cos $A-B$ = cos A cos B + sin A sin B

Using this identity, we can rewrite the expression as:

cos 68 - cos 22 / sin 68 - sin 22
= $cos68<em>cos22+sin68</em>sin22$ / $sin68-sin22$

= $cos(68-22)$ / $sin68-sin22$

= $cos46$ / $sin68-sin22$

Since cos 46 is a constant value, we can further simplify the expression by finding the values of sin 68 and sin 22:

sin 68 = sin $90-22$ = cos 22 = 0.927
sin 22 = sin 22 = 0.374

Now we can substitute these values back into the expression:

= cos 46 / $0.927-0.374$

= cos 46 / 0.553

= 0.718 / 0.553

= 1.301

Therefore, the value of cos 68 - cos 22 / sin 68 - sin 22 is approximately 1.301.