Page 178 - ABCTE Study Guide_Neat

Answer

The correct answer is C. Move the decimal 8 places to the right, which means you will need 5 placeholder
zeroes. Put the commas in to make the number easier to read. Note that choice A has the right number of
zeroes, but the decimal point is in the wrong place.

Convert from Standard Form to Scientific Notation

To write a number given in standard form as a number in scientific notation, there are two steps.

First, write the decimal number. Remember, you can only have one place to the left of the decimal. You
can have as many places to the right as necessary. Drop any placeholder zeroes.

Examples

517,000 becomes 5.17 0.0004906 becomes 4.906

Second, raise the 10 to the correct power. To determine the power, count how many places you needed
to move the decimal to make your decimal number. The exponent will be positive if the standard form was
a big number (greater than 1). The exponent is negative if the standard form of the number is between 0
and 1.

Examples

5
517,000 = 5.17 x 10 (the decimal has to move 5 places)
4
0.0004906 = 4.906 x 10 (the decimal has to move 4 places)

Question

Write 0.00259 in scientific notation.

-4
A 25.9 x 10

-3
B 2.59 x 10

2
C 0.259 x 10

3
D -2.59 x 10

Answer

The correct answer is B. It has the decimal number properly formatted, and the number of the exponent is
correctly counted. Choice D is similar, but the original number was positive, so the negative sign belongs
to the exponent, not the decimal number.