M2.2.7 For the adult
Problems in two steps
How do I know if a problem needs adding or taking away?
What this chapter teaches
A bar model shows the whole on top and its parts underneath. Know the parts? Add. Know the whole and one part? Take away. A word like "more" does not always mean add.
Three questions to ask
There is no one right wording. Listen for the idea.
- How would you draw a bar model for 93 birds when 58 are hens?
- Why can a story with the word more need a take away?
- Can you make up a story that needs two steps to solve?
After the chapter, the learner can
- Draw a bar model to decide whether to add or take away
- Solve a problem that needs two steps
- Find how many more you need to get from 37 to 50
What they copy into their notebook
Draw the whole on top and its parts under it. Know the parts? Add. Know the whole and one part? Take away. Missing part: 50 − 37 = 13.