Start with this short video, then scroll down for the full guide.
Why This Matters for Nursing: Medication doses often come in fractions. If a patient needs ½ tablet in the morning and ¼ tablet at night, you need to know the total: ¾ tablet per day.
A fraction represents a part of a whole. It has two parts: - Numerator (top): How many parts you have - Denominator (bottom): How many equal parts make the whole
To add or subtract fractions, the denominators MUST be the same. If they're not, you need to find a common denominator first.
Same denominators? Just add/subtract the numerators. Keep the denominator the same.
"Denominator = Down Below" (both start with D)
Think of the denominator as the "name" of the fraction—you can only combine fractions with the same name!
Just like you can't add 3 apples + 2 oranges and call it "5 apples," you can't add ⅓ + ¼ directly.
LCD = 12
Convert each fraction:
1/4 = ?/12 → 1×3 = 3, so 1/4 = 3/12
Add the new fractions:
4/12 + 3/12 = 7/12
Answer: 7/12
Problem: 3/7 + 2/7
Step 1 — Check the denominators. Look at the bottom numbers of both fractions. The first fraction has 7 on the bottom. The second fraction also has 7 on the bottom. They match! That means we can add these directly without any extra work.
Step 2 — Add the top numbers (numerators). When the denominators are the same, you only add the tops: 3 + 2 = 5
Step 3 — Keep the bottom number the same. Don't touch the denominator. It stays 7.
Step 4 — Check if we can simplify. Can we divide both 5 and 7 by the same number? 5 is prime, and 7 is prime, so no — we're done.
Answer: 5/7
The worked examples and practice problems are the part that actually prepares you for the TEAS.
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