Answer:
0.0000000101 = 1.01×10^-8
Explanation:
Identify the leading non-zero digit and its place value.
Here, that is 1 in the place 8 to the right of the decimal point.
Write the mantissa starting with that digit, followed by a decimal point and the remaining digits of the number:
mantissa = 1.01
The multiplier is a power of 10. The power is the negative of the number of places to the right of the decimal point where the leading digit is found. Here, the power of 10 is -8. That means your number in scientific notation is ...
0.0000000101 = 1.01×10^-8
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Additional comment
If you write the number in a cell of a spreadsheet, then format that cell as "scientific", you get ...
1.01E-08
The "E" is equivalent to "×10^".
Your calculator may give you a similar result when you tell it to format the number in scientific notation.