standard_description: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
problem_activity: Narrative
The purpose of an Estimation Exploration is to practice the skill of estimating a reasonable answer based on experience and known information.
Launch
Groups of 2
Display the expression.
“What is an estimate that’s too high? Too low? About right?”
1 minute: quiet think time
Activity
“Discuss your thinking with your partner.”
1 minute: partner discussion
Record responses.
Student Facing
\(4 \times 18\)
Record an estimate that is:
{"table": [{"_attributes": {"align": "center", "border": "1"}, "thead": [{"tr": [{"th": [{"_attributes": {"scope": "col", "style": "text-align:center"}, "_value": "too low"}, {"_attributes": {"scope": "col", "style": "text-align:center"}, "_value": "about right"}, {"_attributes": {"scope": "col", "style": "text-align:center"}, "_value": "too high"}]}]}], "tbody": [{"tr": [{"td": [{"span": [{"_attributes": {"class": ["math"]}, "_value": "\\(\\phantom{\\hspace{2.5cm} \\\\ \\hspace{2.5cm}}\\)"}]}, {"span": [{"_attributes": {"class": ["math"]}, "_value": "\\(\\phantom{\\hspace{2.5cm} \\\\ \\hspace{2.5cm}}\\)"}]}, {"span": [{"_attributes": {"class": ["math"]}, "_value": "\\(\\phantom{\\hspace{2.5cm} \\\\ \\hspace{2.5cm}}\\)"}]}]}]}]}]}
Student Response
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Activity Synthesis
Consider asking:
“Is anyone’s estimate less than ___? Is anyone’s estimate greater than ___?”
“Based on this discussion does anyone want to revise their estimate?”


aligns: no