Adding fractions: a/b + c/d = (ad + bc) / bd
Multiplying: a/b × c/d = ac / bd
Dividing: a/b ÷ c/d = a/b × d/c
Mixed → Improper: Whole × Denom + Num / Denom
Decimal → Fraction: 0.75 = 75/100 = 3/4
Cross multiply: a/b = c/d → ad = bc
Example: 3 tabs / 150mg = x / 250mg
→ 150x = 750 → x = 5 tablets
% → Decimal: 45% = 0.45
Decimal → %: 0.08 = 8%
Find %: 20% of 350 = 0.20 × 350 = 70
% increase: (New − Old) / Old × 100
% decrease: (Old − New) / Old × 100
Example: Doctor orders 500mg.
Available: 250mg tablets.
500 / 250 × 1 = 2 tablets
| Conversion | Value |
|---|---|
| 1 kilogram (kg) | = 1,000 grams |
| 1 gram (g) | = 1,000 milligrams |
| 1 liter (L) | = 1,000 milliliters |
| 1 meter (m) | = 100 centimeters |
| 1 cm | = 10 millimeters |
| 1 cc | = 1 milliliter |
| Conversion | Value |
|---|---|
| 1 kg | = 2.2 pounds |
| 1 inch | = 2.54 cm |
| 1 ounce | = 30 mL |
| 1 cup | = 240 mL |
| 1 tablespoon | = 15 mL |
| 1 teaspoon | = 5 mL |
°F to °C: (°F − 32) × 5/9
°C to °F: (°C × 9/5) + 32
Normal body temp: 98.6°F = 37°C
Military time: Add 12 to PM hours
1:00 PM = 1300, 5:30 PM = 1730
IV drip rate: Volume (mL) / Time (hr) = mL/hr