Pharmacology I Math Review

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

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

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

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

Decimal rules Zeroes added AFTER (to the right) of the digit DO NOT change its value Example 0.8 = 0.80000 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

Fraction to Decimal Divide the numerator by the denominator Example 6/30 = 6 ÷ 30 = 0.2 3/57 = 3 ÷ 57 = 0.0526 ~ 0.053

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

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 = 1220.0 0.893 x 1000 = 893

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 = 0.0008

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 ~ 4.3 5.68 ~ 5.7