Idea 20of 21Builds onGraph the savings
Between and beyond the dots
How do you find a missing point on a pattern's graph?
Today you'll discover
- why the dots line up
- how to read between them
- how to read beyond them
Think firstTerm 4's dot is missing
What value should term 4's dot have?
Decide first, then press Next. Use the line the dots make.
A grid with term numbers 0 to 10 along the bottom and values up the side. Dark dots at terms 1, 2, 3, 5 and 6 (5, 8, 11, 17, 20), with rings at term 4 and term 9. A straight line joins the dots; the ring at term 4 fills at 14, and the line extended reaches 29 at term 9.
See the whole ideathe big idea and the key word, in one place
The big idea
Missing points lie on the pattern's line: read between the dots, or extend the line.
Compare themInterpolate: find a point between dots you have. Extrapolate: find a point beyond them, by extending the line or using the rule.
Easy to get wrongA point read off a graph can be a little off. Check it with the rule.
Key words
- interpolate
- to find a point between points you already have
- extrapolate
- to find a point beyond the points you have
Ready to use it?
- Find a missing point on a pattern's graph.
- Extend a pattern's graph to predict a later point.