Adding fractions worksheets
From like denominators to unlike ones: each problem is printed with stacked fractions, and the answer key gives every sum in simplest form.
How to solve them
- Same denominators: add the numerators and keep the denominator.
- Different denominators: find the least common multiple of the denominators and rewrite both fractions with it.
- Add the numerators, then simplify. Change an improper result into a mixed number.
Ready-to-print adding fractions worksheets
Nine fixed sets — three per level. Each PDF has the problems followed by the answer key.
Levels
| Level | Problems | Grade |
|---|---|---|
| Easy | Like denominators (3/8 + 4/8) | 3–4 |
| Medium | One denominator is a multiple of the other (1/3 + 5/12) | 4–5 |
| Hard | Unlike denominators to 12 (3/4 + 2/5) | 5 |
Common mistake
Adding the denominators: 1/2 + 1/3 is not 2/5. A quick sense check catches it — 2/5 is less than 1/2, so it can't be 1/2 plus something. Practising least common multiples first makes unlike denominators much easier.
Charts that help
- Fraction chart (fraction wall) — free printable PDF
More math generators: multiplication, long division, comparing fractions, multiplying fractions, least common multiple (lcm), greatest common factor (gcf), area, place value, addition, subtraction, combining like terms. Or print a whole grade: 4th, 5th and 6th grade math.
Frequently asked questions
Are the answers in simplest form?
Yes, every answer is reduced, and sums bigger than one are written as mixed numbers (1 1/12).
What should students learn before adding unlike fractions?
Equivalent fractions and least common multiples. Try the LCM worksheets first if finding a common denominator is slow.
Is there an answer key?
Yes. The PDF always ends with an answer key for the same problems, so you can print the questions for students and keep the key. Every answer is checked by automated tests.
Can I print the same worksheet again later?
Yes. Every sheet has a set number (the seed) printed in the footer and saved in the page address. Open the same link, or type the same level, count and set number, and you get exactly the same problems and answer key.