1. Carolina has a box of 30 matches. She begins to make the number 2022 using matchsticks. The diagram shows the first two digits. How many matchsticks will be left in the box when she has finished?
A 20
B 19
C 10
D 9
E 5
Solution
D

Each of the twos in " 2022 " requires 5 matches, so 15 altogether. And she needs six matches for the zero, which leaves $30-15-6=9$ matches.