Today’s homework. A bigger story.
Pick a topic, meet the people behind the ideas, and try something together.
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What is hiding in the cups?
Imagine two identical cups hiding the same number of counters. There are 3 more counters outside, and 11 altogether. What number is hiding?
The legacy behind the lesson
Al-Khwarizmi was a mathematician who worked at the House of Wisdom in Baghdad.
He wrote a book about solving equations. It showed how mathematics could help with everyday problems.
Our word algebra comes from al-jabr, a word in the title of his book.
“What everyday mystery could you solve with numbers?”
Solve the mystery of the cups
Gather: Two paper cups and 11 counters. Use large paper squares for young children.
- 1
Draw two identical cups, plus 3 counters, on one side of a page. Write 11 on the other side.
- 2
Pretend each cup hides the same number. Remove 3 from both sides: 8 remain to share.
- 3
Share those 8 equally between the two cups. How many belong in each?
- 4
Check your answer: 4 + 4 + 3 = 11. Make a new mystery for someone else.
Check your thinking
Two cups plus 3 counters make 11. Each cup hides the same number.