A reasonable conjecture is a prediction about a mathematical pattern, relationship, or result based on examples, representations, and known facts—for example, predicting the next terms in a repeating or growing pattern, an unknown quantity in an addition or subtraction situation, or a property shared by familiar shapes. The conjecture should fit the available evidence and can be checked with additional cases; formal proof, generalization beyond accessible whole numbers, and advanced counterexample analysis are not included.
A conjecture is a careful prediction based on what you notice in examples. To make one:
Example:
What number comes next?
Step 1: Notice the pattern.
Each number is more than the number before it:
Step 2: Make a conjecture.
If the pattern keeps adding , the next number should be
So, our conjecture is that the missing number is .
Step 3: Check it.
The next number after would be , and . This fits the pattern, so our conjecture is reasonable.
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