1. How many times does the digit 9 appear in the answer to $987654321 \times 9$ ?
A 0
B 1
C 5
D 8
E 9
Solution
B

There seems no better method here than just doing the multiplication.
$$
9 \times 987654321=8888888889 \text {. }
$$

So the number of times that the digit 9 occurs in the answer is 1 .