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 read, build and break apart whole numbers up to 200 and to say how numbers are used in everyday life. The museum offers one account of how numbers are written in places, with units, tens and hundreds; the objects, the drawings and all the practice your class brings. Adding and subtracting with objects, diagrams and equations is not covered here. 1
Curriculum expectations, with their official codes
- B1.1 read, represent, compose, and decompose whole numbers up to and including 200, using a variety of tools and strategies, and describe various ways they are used in everyday life
2 The lesson
How can one number be taken apart?
Pick a number between 100 and 200. The expectations ask you to compose and decompose it with tools: try bundles of ten, a hundred chart or place-value blocks, and compare the ways you found.
Go deeper
The record on algorism has a picture for young readers. About twelve hundred years ago a scholar in Baghdad named al-Khwarizmi wrote a book teaching people to calculate with nine numerals that came from India, together with zero 2 3. With these numerals you only need to move a digit to change its value: a one can mean one, ten or a hundred! 2 3
Think about it
A one can mean one, ten or a hundred, depending on where it stands. Why does it matter that you put each digit in the right place when you write a number?
Into the museum
- Algorism: the whole story of the nine numerals and the zero.
- al-Khwarizmi: the scholar who wrote the book, and where he worked.
- al-Khwarizmi's Book of Arithmetic: the book, and the words that came from his name.
Try this
Read the record on algorism. Choose a number under 200, write it in its places, and say how many hundreds, tens and ones it has.
3 Check yourself
Nothing here is marked or sent anywhere. It is for you.
In your own words: what does Algorism (reckoning with Indian decimal numerals in al-Khwarizmi's book of arithmetic) have to do with this lesson?
Compare with the card
Nine numerals and a zero. Algorism is a way of writing and working numbers with nine numerals and a zero, in which each place takes its value from its position: units, then tens, then hundreds. Muhammad ibn Musa al-Khwarizmi wrote a book on it in Baghdad, through which the Indian numerals and the decimal system entered the Islamic world. How would you show your number as tens and ones?
I can now