Sender: Don
Subject: problem solving
Date: Mon, 24 Nov 1997 18:53:10 -0500

Hope you can help !!!! my daughter is in the 4th grade.. she has brought home a homework paper and the subject is problem solving. she does not understand what is expected of her. I have tried to help, but I do not understand either.

She is to use the Guess and check Strategy.

Ben knows 100 of his neighbors by name. Ten are fish. The rest are frogs and turtles. He knows the names of twice as many turtles as frogs. How many turtles does he know by name.?

Please help by explaining the guess and check strategy for a problem like this.

Hi Don,

I hope I can help. The guess and check strategy is exactly what it sounds like: you make a guess and then check to see if it is a solution. The idea is that with each successive guess you get closer to an answer.

First, let's look and see what we know. There are 100 neighbours, 10 are fish. We are interested in the number of turtles. We know that there are 90 turtles and frogs together.

With the guess and check method, it is often helpful to set up a table or chart to record the guesses.

The headings on the chart could be

Number of frogsNumber of turtlesTotal number of turtles and frogs

There are twice as many turtles as frogs. So let's try it. If there are 20 frogs, then there will be 40 turtles (twice as many). That's OK but it only gives us a total of 60, not 90. So my second guess should be a larger number of frogs and turtles. Let's try 40 frogs and 80 turtles; that gives us 120, not 90. My next guess would be in between the previous 2 guesses: eventually, using this idea we end up choosing 30 frogs and 60 turtles and yes! it gives me a total of 90.
Number of frogsNumber of turtlesTotal number of turtles and frogs
204060
4080120
.........
306090

Hope this helps!

Diane

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