options: Use rational approximations of irrational numbers to compare the size of irrational numbers, locate them approximately on a number line diagram, and estimate the value of expressions (e.g., p^(2)). For example, by truncating the decimal expansion of Ö2, show that Ö2 is between 1 and 2, then between 1.4 and 1.5, and explain how to continue on to get better approximations.

Know that numbers that are not rational are called irrational. Understand informally that every number has a decimal expansion; for rational numbers show that the decimal expansion repeats eventually, and convert a decimal expansion which repeats eventually into a rational number.
problem_activity: Task
Jessica evaluates $\sqrt{2}$ on her calculator which shows a value of
$$
1.4142136.
$$
She then writes
$$
\sqrt{2} = 1.4142136.
$$
Is Jessica correct?  Explain.
Explain, in terms of the structure of the expression $(1.4142136)^2$, why
it can not be equal to $2$.
Use the reasoning of part (b) to explain why $\sqrt{2}$ can not be equal
to any terminating decimal.


correct_option_index: 0

1