M2.1.5 For the adult
Rounding and estimating
A sack has 3 472 seeds. Why do people say about 3 500?
What this chapter teaches
Rounding swaps a number for a close one that is quicker to use. Look at the digit one place to the right of the place you round to: 5 or more goes up, 4 or less stays. An estimate is a careful guess, so say about.
Three questions to ask
There is no one right wording. Listen for the idea.
- How would you round 3 472 to the nearest 100, and how do you decide?
- Why does 250 round up to 300 and not down to 200?
- How could you estimate the beans in a bowl without counting every one?
After the chapter, the learner can
- Round a number to the nearest 10, 100 or 1 000
- Estimate the seeds in a sack by counting one cupful
What they copy into their notebook
Look at the digit one place to the right. 5 or more rounds up. 4 or less rounds down. 3 472 is 3 500 to the nearest 100. An estimate is close, not exact.