I was like a kid at Christmas time last week. My newest math tools came in the mail! My presents to myself and my students consisted of a set of base 10 units including ones, tens rods and hundreds flats. I also acquired 10 beautiful number lines with the zero in the middle and the positive and negative regions extending to the right and left. There were magnetic fractions circles which started from one red whole circle and went all the way down to 12ths with decimals and percents on the other sides. I had decided to purchase a set of unifix cubes at the last minute and was glad I did since they were the first math tools that I used in my next lesson. One of my third graders was learning how to find the missing amount in word problems dealing with addition, subtraction, multiplication and division. She is a very bright and needed an extra challenge so I decided to teach her about how to find a variable in an algebraic equation.
We started with a simple equation like x + 8 = 15. I had her pick two different colors for the unifix cubes. She picked red and blue. I gave her 15 red cubes and 8 blue and placed them on the white board right in the blank spaces where then numbers would go in the equation. I told her the objective was to make both sides equal in amount. She said she would need 7 more blue cubes then. Success! I did another algebraic equation with her this time giving her 14 yellow cubes that she would place at the beginning of the equation right before a subtraction sign. The equation looked like this. 14 - x = 6. After giving her 6 green cubes I again told her that we needed to make both sides of the equation equal in amount, meaning that we would have to take an amount away from 14 to make it equal to 6. "Oh!, she exclaimed, "You mean I have to take away 8 yellow cubes from 14 right?" I smiled. "Exactly!" The amount that I pay for my math tools is worth it when I see the light of understanding in their eyes.