1. Pharmacology I
Math Review

2. Fractions – add or subtract
Convert to equivalent fraction with like denominators
Perform math on numerators
Example
½ + 1/8 = 4/8 + 1/8 = 5/8
11/12 – 17/24 = 22/24 – 17/24 = 2/24

3. Fractions - multiplication
Multiply numerators and multiply denominators
Example
¾ x 2/3 = 6/12
11/2 x 3/7 = 3/2 x 3/7 = 9/14

4. Fractions – division
Invert the divisor, then multiply the numerators and denominators
Examples
7/8 ÷ 3/5 = 7/8 x 5/3 = 35/24
Reduce answer to lowest terms 1 11/24
8/12 ÷ 3/7 = 8/12 ÷ 7/3 = 56/36
Reduce answer to lowest terms = 1 5/9

5. Decimals
A fraction with a denominator of 10, 100, 1000 or any multiple of 10
The position of the number in relation to the decimal point indicates its value
Example
8.0 vs 0.8 vs. 0.08

6. Decimal rules
Zeroes added AFTER (to the right) of the digit DO NOT change its value
Example 0.8 =
ALWAYS place a zero to the LEFT of the decimal point if there is not a number to go there
Example 0.8 NOT .8

7. Fraction to Decimal Divide the numerator by the denominator Example
6/30 = 6 ÷ 30 = 0.2
3/57 = 3 ÷ 57 = ~ 0.053

8. Decimal to Fraction Place the number in the numerator place
Make the denominator be 10 or a multiple of it
Reduce to lowest terms
Example
0.93 = 93/100
5.03 = 5 3/100

9. Decimals - multiplying
When multiplying by a power of ten, move the decimal point as many places to the right as there are zeroes in the multiplier
Example
12.2 x 100 =
0.893 x 1000 = 893

10. Decimals - dividing
When dividing by a power of ten, move the decimal point to the left as many places as there are zeroes in the divisor
Example
63.8 ÷ 100 = 0.638
0.008 ÷ 10 =

11. Rounding
Do not change the number in tenths place, if the number in hundredths place is 4 or less
Increase the number in tenths place by 1 if the number in hundredths place is 5 or more
Example
4.32 ~ ~ 5.7