Understanding Why
Go beyond knowing *that* something is true: ask *why* it is true and *how* it works
What a learner can do afterwards
- Recognize a question that asks for a reason why something happens
- Explain the reason behind a rule or method, for example: 'We carry the ten because 13 ones is the same as 1 ten and 3 ones'
- Connect a new idea to something familiar and explain which parts match
1 · Read
You may know a fact before you can explain its reason. Ask 'Why does that happen?' or 'How does that work?' Then explain the reason in your own words and check it with an example. Asking starts the search. Repeating a rule alone does not show whether you can explain why it works.
Mia adds 6 + 8 and gets 14 ones. Why write 4 in the ones column and 1 in the tens column? Ten ones form one full ten, and 4 ones remain. The 1 in the tens column stands for that ten. Grouping the cubes does not add or take away any cubes.
You can explore this reason with counters. Put ten together and count what remains. Fewer than ten ones cannot form a full ten. Check an explanation with another example too. Adding 3 + 4 gives 7 ones, so adding does not always make a full ten.
A familiar idea can help explain a new one. Writing a ten in the tens column is like bundling ten single cubes. Both use ten ones to make one ten. Name the part that matches. A shared color or familiar name does not explain the grouping.
Ask why, explain the reason and check an example. When a familiar idea helps, say which parts match.
This lesson, its practice questions and flashcards were written for this dataset.
Both readings were written for this dataset.
More to read
Follow the question with a check
Someone tells you that 15 ones can be written as 1 ten and 5 ones. You wonder why the 1 means ten.
Take 15 counters. Put ten in a group, leaving five outside. Point to the group as you explain the tens digit. Point to the five single counters as you explain the ones digit.
If part is still unclear, say which part you want to ask about.
Keep a question in your notes
A note can hold a question you want to return to. You could write, 'Why does grouping cubes leave the total unchanged?'
Count the cubes before and after grouping. Add what you find: 'These are the same cubes. None were added or removed.'
Later, use the note to try explaining the reason in your own words. Mark any part you still want to discuss.
2 · Watch
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Where it sits
Learn first
Nothing; this is a starting point.
Optional connections
Where this leads
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.