### Question 1

With pencil and paper, use dots-and-boxes to compute $2130 \div 10$.

Can you explain why, with unexplosions, the answer will be $213$? Do look for groups of ten in your picture.

Most people say that to divide a number that ends with zero by ten, just cross off the final zero from the number. Can you explain now why that action is sure to lead to the correct answer?