standard_description: Prove that, given a system of two equations in two variables, replacing one equation by the sum of that equation and a multiple of the other produces a system with the same solutions.
problem_activity: Problem 1
a.   Split 18 counters equally into groups of two.
i. Write a multiplication equation to represent this situation.
ii. How many groups of counters do you have?
b.   How is this similar to Anchor Task #1 from Lesson 3? How is it different?
Problem 2
a.   Casey bought the following stickers. She wants to put 5 stickers in each goodie bag for her birthday party.
[IMG]
i. Write a multiplication equation to represent this problem.
ii. How many goodie bags did Casey fill with stickers?
b.    A grocery store puts 30 watermelons on display. They arrange them in rows of 10.
i. Write a multiplication equation to represent this problem.
ii. How many rows of watermelons are there?
Problem 3
a.   Draw a picture or write a story to represent the following multiplication situation.
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$$\times \ 4 = 12$$
b.   Find the number that makes the equation true. Rewrite the equation with the solution.


aligns: no