Draft: this lesson was written with AI help and has not yet been read by a human editor.
1 What your class asks
This lesson asks you to describe how a variable is used and to use one in problems. The museum offers a record on algebra, the branch of mathematics that solves problems by positing an unknown. Choosing a letter or symbol and using it in your own problems is the class's work. 1
Curriculum expectations, with their official codes
- C2.1 describe how variables are used, and use them in various contexts as appropriate
2 Before you start
A thought to carry into the lesson.
3 The lesson
What can a letter stand for?
Make up a problem with a number you do not know yet. Give the unknown a letter. What does the letter stand for in your problem?
Go deeper
Al-Khwarizmi wrote a book about finding a number you do not know. He used words, not symbols, for everything: the unknown was called a “thing”, and its square a mal 2. The science of algebra takes its name from the word al-jabr, which he used as the title of his book 3.
Think about it
Al-Khwarizmi wrote in words, not symbols, and called the unknown number a “thing”. In your problem about marbles, which would help a friend more, the word “thing” or a letter, and why?
Into the museum
- Algebra (al-jabr): where the name of the science comes from.
- The Book of al-Jabr and al-Muqabala: the book, and how it writes everything in words.
- al-Khwarizmi: the scholar who wrote it.
Try this
Read the record on algebra. Write a short problem about an unknown number of marbles, give the unknown a letter, and explain to a partner what it stands for.
4 Check yourself
Nothing here is marked or sent anywhere. It is for you.
In your own words: what does Algebra (al-jabr) have to do with this lesson?
Compare with the card
Solving by positing an unknown. Algebra is the branch of mathematics that solves problems by positing an unknown and handling equations by general methods. What could you use to stand for an unknown in a problem of your own?
I can now