1. Explain in two different ways why if a b and c is a whole number, then a c b c .
2. John claims that he can get the same answer to the problem below by adding up (begin
with 4 + 7) or by adding down (begin with 8+ 7). He wants to know why an
1. Jonah has a collection of marbles. He notices that if he borrows 5 marbles form a friend,
he can arrange the marbles in rows of 13 each. What is the remainder when he divides
his original number of marbles by 13?
2. Gina buys apples from an