Predict the result
Which of these three numbers are written in scientific notation?
A negative coefficient is allowed.

Set up the model
Use a coefficient times ten raised to an integer power.
The absolute value of the coefficient is at least one and less than ten.

Work the example
Negative nine point six seven times ten to the twentieth qualifies.
One hundred forty-five times ten to the negative eighth has a coefficient that is too large.
One point four five alone is not written in the required product form.
The coefficient rule uses absolute value.

Check the result
Classify forty-two point six seven times ten to the thirteenth,
seven point one one three times ten to negative two,
and negative eighty point nine one.
Take eight seconds to think before the answer appears.
[Eight-second silent pause to work; the answer remains hidden.]
The answers are no, yes, and no.
Only seven point one one three is a qualifying coefficient in the required form.

Interpret the result
Check both the coefficient and the power-of-ten form.
Use the original task and check that your result fits its meaning.