Erika and her 3 siblings are drawing with chalk outside. Another 3 friends join them and ask if they can help with the drawing. Erika loses 2 pieces of chalk as they are counting and the group realizes there isn't enough chalk for everyone. Erika's mom brings out another 12 pieces of chalk for them to share and there is now enough chalk for everyone to have 3 pieces each. How many pieces of chalk did Erika and her siblings originally have? Let's think first. Chain of thought:
Altogether, there are 1 Erika + 3 siblings + 3 friends = 7 people drawing outside. The group has a total of 7 people * 3 pieces of chalk each = 21 pieces of chalk altogether. Before Erika's mom helped, they had 21 total pieces of chalk - 12 pieces of chalk Erika's mom brought = 9 pieces of chalk. Then adding the chalk that Erika lost shows that the group originally had 9 pieces of chalk + 2 lost pieces of chalk = 11 pieces of chalk.
Therefore, the answer is 11.