is a irrational number where as 22/7 is a rational number as it is written in (p/q) form where q not equal to 0
Value of is 3.1415926535897932384626433832795...
while value of 22/7 is 3.1428571428571428571428571428571...
We can clearly see that their is a difference between value of and value of 22/7. Difference between both is of 0.00126448926734961868021375957764. But that difference is so small that we could neglect this difference.