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Using Algebra/Variables. How to use this strategy:Look for a pattern that can be described in words and/or a general formulaFinding Patterns:Look at the sequences of numbersLook at input/output table for ruleStart with simpler case firstUse finite differences. Using Algebra/Variables. When to
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1. Problem Solving Strategies Algebra/Use a Variable
Look for a Pattern
Make a List
Solve a Simpler Problem
2. Using Algebra/Variables How to use this strategy:
Look for a pattern that can be described in words and/or a general formula
Finding Patterns:
Look at the sequences of numbers
Look at input/output table for rule
Start with simpler case first
Use finite differences
3. Using Algebra/Variables When to use this strategy:
The phrase ‘any number’ is used
There is a list of numbers that can be generated from the problem
There is an input/output that can be described as a rule
A large number of cases are involved
4. Example 1 Determine the sum of the first 50 odd counting numbers.
Step 1: odd counting numbers are 1, 3, 5, 7, 9 … and so on. I am adding together the first 50 of these odd numbers starting with 1+3+5…
Step 2: The plan will be to start with simpler problems and look for a pattern in the smaller/simpler sums
5. Example 1 Step 3: Use an input/output table to keep track of the simpler sums and look for a pattern.
Input-how many odd #’s am I adding?
Output-what is the sum?
Do you see the pattern?
6. Example 1 The pattern that related the input to the output is:
Sum of n number of odd numbers is n x n (the sum of the first 3 odd numbers was 3 x 3)
So the sum of the first 50 0dd numbers is 50 x 50, or 2500
Step 4: Look back and verify answer
7. Example 1 Imagine each odd number represented by tiles in the following shapes (note the number of tiles used represents the odd number, show below are 1, 3 and 5)