Balancing Act
Have you ever seen a pan balance? Pan balances used to be popular in food markets: a merchant could place a measured weight on one pan, and measure the amount of food that a buyer wanted to purchase.
We don’t use them much today. But pan balances can help us solve a linear equation with one variable.
Take the algebra problem 2x + 4 = 10. See how it looks on a pan balance.
Notice how the two pans are at the same level; the distance from the ground is the same. That means that the amount in each pan is the same.
So here’s a question: If all the blocks (squares) weigh the same amount, how many are in one bag? Write your guess below. (You’ll find out on the next page.)
