AES number of Round calculation I wondering about the formula for calculating the number of AES rounds.

The formula is $R=(\text{Keysize}/32)+6$

I would like help understanding why we divided by $32$ and add $6$ in this formula.
i wanna help to understand why we divided by 32 and add 6 in this
  formula


AES is defined for three key-sizes: 128, 192 and 256 bit with 10, 12 and 14 rounds respectively. These round numbers have been tabulated originally (that is no continuous function was given) and why these were chosen is because they offered the optimal (or at least a very good) trade-off between security and performance. 

Now if you want to turn these three points into a continuous function, you can do interpolation and this will return you the function you found: $$R=k/32+6$$

as clearly $10=128/32+6, 12=192/32+6$ and $14=256/32+6$.