Differentiate Between Valid and Invalid Approaches
Lesson
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There are many different ways to solve a problem, however it is important to make sure that the approach you use is a valid (correct) one.

Look for patterns, relationships, and try to visualize what is going on in the problem. Then use what you've learned to solve the original problem.

 

Example

Cartoon man trying to hit a nail with a hammer while on a ladder A man climbs a ladder 6 feet high to pound in a nail. Every minute the man was able to climb 2 feet up the ladder but then would slide 1 foot down.  How many minutes would it take the him to climb the ladder?

Valid or Invalid

Valid

 He gains one foot every minute on the ladder, 2-1=1, so it would take him 6 minutes to climb the ladder 6 feet.

Invalid

 6+2+1=9, Just taking the numbers and adding them together is an incorrect way to solve the problem.

Valid

 

 

 

 

   

         0         1          2          3          4          5          6         7
                              
                            = 1 minute, count the number of arrows and
there were 6 arrows.

Drawing a picture is a good way to solve a problem.

Invalid

 

 

 

 

        0         1          2          3          4          5          6         7

                           = 1 minute, count the number of arrows and
there were 5 arrows, however remember once he gets to 6 feet he'll slid back to 5 feet. So he has to get 7 feet so he can land on 6 feet to pound in the nail.

 

Remember: Use the method of solving a problem that you're most comfortable with. Then when the problem is done ask yourself " Is this what the question is asking for? Is the problem solved correctly."

Go to Practice

 

 

 

 
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