Explanation:

In ΔADE,
∠ADE=180 − (∠AED + ∠EAD)
= 180 − (38 + 102)
= 40$$\text{degree}$$
⇒∠ADC = 40$$\text{degree}$$
square ABCD is a cyclic quadrilateral.
∴∠DCB + ∠DAB=180
⇒∠DCB = 180 − ∠DAB
∠DCB = 180 − 102
∠DCB = 78$$\text{degree}$$
In ΔDFC,
∠DFC=180 - (∠FDC+∠FCD)
∠DFC = 180 − (40 + 78)
∠DFC = 180 − 118
∠DFC = 62$$\text{degree}$$
∠AFB = ∠DFC = 62$$\text{degree}$$.
Difference between $$\mathrm{\angle }BAD$$ and $$\mathrm{\angle }AFB$$ = 62 - 40 = 22$$\text{degree}$$