Final answer:
The number 87 in standard form is just '87'. For scientific notation, 87,449 with four significant figures is 8.745 × 10^4, and 0.000066600 with five significant figures is 6.6600 × 10^-5.
Step-by-step explanation:
To write the number 87 in standard form, you simply write it as '87'. Standard form is just the regular way of writing numbers without using exponents or scientific notation. However, if we went into scientific notation for other numbers, for instance, to write the number 87,449 in scientific notation with four significant figures, we would express it as 8.745 × 104. For a smaller number, like 0.000066600 with five significant figures, we would write it as 6.6600 × 10-5.
As an example of standard notation, the number 79,345 can be expressed as 7.9345 × 104. When dealing with very large or very small numbers, scientific notation becomes more practical to avoid writing many zeros. For instance, the dollar amount of $79.2 billion in scientific notation is expressed as $7.92 × 1010.