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Students figure out people's ages by doing simple math calculations.
age, arithmetic, birthday, calculate, math, puzzle, year
This lesson includes two puzzle activities students can do to exercise their math skills and impress their parents, neighbors, and relatives. In both activities, kids provide adults with directions that require simple math computations in order to help the kids -- magically! -- figure out the ages of the other people. Following are the directions students will provide as they work these two puzzles on their peers or adult acquaintances.
Puzzle 1 (for students who can do simple addition and subtraction and multiply by 5)
Encourage students to try this puzzle in advance a few times -- using random numbers (ages) -- to see whether it works. That will provide math practice for students. For this activity, you might provide, or students might create, a simple chart with the following headings:
Challenge Question: See whether students can figure out why the puzzle works!
Puzzle 2 (for students who can add larger numbers and multiply by 50)
Challenge Question: See if students can figure out why the puzzle works!
Note: The numbers 1752 and 1751 will work only in the year 2002. If you are doing this puzzle activity in 2003, add 1 to each of those numbers (use 1753 and 1752); if you are doing the puzzle in 2004, add 2 to each of those numbers (use 1754 and 1753) and so on.
Students do a series of calculations to help them see that these puzzles work. If they come across an example that does not work, they redo the calculation to find their error(s).
Lesson Plan Source
MATHEMATICS: Number and Operations
GRADES 3 - 5
NM-NUM.3-5.3 Compute Fluently and Make Reasonable Estimates
GRADES 6 - 8
NM-NUM.6-8.3 Compute Fluently and Make Reasonable Estimates
GRADES 9 - 12
NM-NUM.9-12.3 Compute Fluently and Make Reasonable Estimates
MATHEMATICS: Problem Solving
GRADES Pre-K - 12
NM-PROB.PK-12.4 Monitor and Reflect on the Process of Mathematical Problem Solving
MATHEMATICS: Reasoning and Proof
GRADES Pre-K - 12
NM-REA.PK-12.2 Make and Investigate Mathematical Conjectures
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