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Converting from decimals to scientific notation

Converting from decimals to scientific notation

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CONVERTING UNITS WITHIN THE METRIC SYSTEM<br />

First and foremost, you need know (i.e., memorize) what each metric prefix represents:<br />

mega- (M) = 10 6 units<br />

kilo- (k) = 10 3 units<br />

BASE UNIT (no prefix) = 1 (i.e., 10 0 ) unit<br />

deci- (d) = 10 -1 units<br />

centi- (c) = 10 -2 units<br />

milli- (m) = 10 -3 units<br />

micro- (μ) = 10 -6 units<br />

nano- (η) = 10 -9 units<br />

When converting <strong>from</strong> one metric unit <strong>to</strong> another, simply move the decimal point a number of<br />

places equal <strong>to</strong> the difference* between the exponents associated with each prefix. When<br />

converting <strong>from</strong> larger <strong>to</strong> smaller units, the number should increase therefore the decimal<br />

should move <strong>to</strong> the right:<br />

e.g. 105 kg (105 x 10 3 g) = ____________ mg (? x 10 -3 g)<br />

-the difference between the exponents for each prefix is 6 (3 – (–3) = 6)<br />

-since you’re converting <strong>from</strong> larger <strong>to</strong> smaller units, the decimal is moved<br />

6 places <strong>to</strong> the right:<br />

105 kg (105 x 10 3 g) = 105,000,000 mg (105,000,000 x 10 -3 g)<br />

When converting <strong>from</strong> smaller <strong>to</strong> larger units, the number should decrease therefore the<br />

decimal should move <strong>to</strong> the left:<br />

e.g. 105 mg (105 x 10 -3 g) = ____________ kg (? x 10 3 g)<br />

-the difference between the exponents for each prefix is –6 (–3 – 3 = –6)<br />

*don’t worry about whether the difference is + or –<br />

-since you’re converting <strong>from</strong> smaller <strong>to</strong> larger units, the decimal is moved<br />

6 places <strong>to</strong> the left:<br />

105 mg (105 x 10 -3 g) = 0.000105 kg (0.000105 x 10 3 g)<br />

*The difference between 2 numbers is one number subtracted <strong>from</strong> another. Remember that<br />

subtracting a negative number is the same as adding a positive number (e.g., 3 – (–3) = 6). The<br />

easiest way <strong>to</strong> think of this is <strong>to</strong> use a number line:<br />

-6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6<br />

The difference between 2 numbers for our purposes is simply the number of positions on the<br />

number line it takes <strong>to</strong> go <strong>from</strong> one number <strong>to</strong> the other.<br />

(e.g., <strong>from</strong> –3 <strong>to</strong> +3 is 6 places, <strong>from</strong> +3 <strong>to</strong> –3 is also 6 places)

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