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: Stage 2: Any Place
Required Preparation
Materials to Gather
Colored pencils, crayons, or markers
Number cards 0–10
Paper clips
Materials to Copy
Blackline Masters
Tic Tac Round Stage 2 Gameboard
Tic Tac Round Stage 2 Spinner

Narrative
Students remove the cards that show 10 before they start. Then they choose six number cards and make a six-digit number. They spin the spinner to get a place value to round to. Students write their number in any space on the board, each partner using a different color. The first player to get three in a row wins.


aligns: no