M3.8.5 For the adult
Solving equations in one step
A balance is level. The left pan holds a bag of x stones and 7 loose stones. The right pan holds 12 loose stones. How many stones are in the bag?
What this chapter teaches
An equation is like a level balance. To solve it, do the same thing to both sides until the unknown is alone. Each step uses the inverse operation, and the answer is always put back to check it.
Three questions to ask
There is no one right wording. Listen for the idea.
- If x + 7 = 12, what do you do to both sides, and why?
- What is the opposite of multiplying by 4?
- How can you check that x = 5 is right for 4x = 20?
After the chapter, the learner can
- Use a balance picture to keep both sides equal
- Solve x + 7 = 12 and 4x = 20
What they copy into their notebook
An equation is a level balance. Do the same to both sides. Use the inverse operation: take away to undo add, divide to undo multiply. Always put the answer back.