Units digit of an expression 1-1

1. Find the units digit of $23 \times 47 \times 84$
a. 4
b. 6
c. 8
d. 0


2. Find the units digit of ${2^4} + {4^2} + {5^6} + {6^5}$
a. 2
b. 4
c. 6
d. 8


3. Find the units digit of $3^{20}$
a. 1
b. 3
c. 9
d. 7


4. Find the units digit of ${2^{25}}$
a. 2
b. 4
c. 6
d. 8


5. Find the units digit of ${2^{75}} \times {3^{50}} \times {7^{100}}$
a. 2
b. 4
c. 6
d. 8


6. Find the units digit of ${4^{75}} \times {9^{50}}$
a. 4
b. 9
c. 6
d. 8