Question: Eric has 20 marbles. He has 12 white marbles, 6 blue marbles, and the rest are green marbles. How many green marbles does Eric have?
Answer with step-by-step thinking: Eric has a total of 12 + 6 = 18 white and blue marbles. Thus, he has 20 - 18 = 2 green marbles.
So the answer is 2.

Question: There are 92 students altogether. Twenty of them ride the school bus home together, 5/8 of the remaining ride their own bike home, and the rest whose houses are near the school walk home. How many students are walking home?
Answer with step-by-step thinking: If there are 92 students and 20 students take the bus home, the number of students who haven't taken the bus is 92 - 20 = 72 students. 5 / 8 of the students who didn't take the bus home ride bikes home, a total of 5 / 8 * 72 = 45 students. The number of students who neither took the bus nor biked home but walked home is 72 - 45 = 27.
So the answer is 27.

Question: Wilma has a garden with 3 types of flowers. The garden has 6 rows, with 13 flowers in each row. Wilma has 12 yellow flowers, two times more green flowers, and the rest consist of red flowers. How many red flowers does Wilma have?
Answer with step-by-step thinking:
The garden has space for 6 * 13 = 78 flowers in total. Wilma has two times more green flowers than yellow flowers, which means she has 2 * 12 = 24 green flowers. That leaves us with 78 - 24 - 12 = 42 red flowers in the garden.
So the answer is 42.