7. There is a sequence of numbers: $1,1,2,2,4,8,12,96,108, \cdots \cdots$, where the 3rd number is the sum of the two preceding numbers, the 4th number is the product of the two preceding numbers, the 5th number is again the sum of the two preceding numbers, the 6th number is again the product of the two preceding numbers... alternating between addition and multiplication. Following this pattern, the unit digit of the 2020th number is $\qquad$
$0$