M3.8.1 For the adult
Letters for unknown numbers
Ravi has a closed box of beans and 5 loose beans. How can he write down all his beans?
What this chapter teaches
A letter can stand for a number we do not know. n + 5 is a box and 5 more, 3n is three boxes, and n² is n times n, which is not the same as 2n.
Three questions to ask
There is no one right wording. Listen for the idea.
- If the box holds 8 beans, how many beans are n + 5?
- What is the difference between 3n and n + 3?
- Try n = 4. Why is n² not the same as 2n?
After the chapter, the learner can
- Write 'a number add 5' as n + 5
- Write 3 × n as 3n and n × n as n²
What they copy into their notebook
A letter stands for an unknown number. n + 5 is a box and 5 more. 3n is 3 × n. n² is n × n, and it is not 2n.