Question 1

How do I add fractions with different denominators?

Accepted Answer

Find a common denominator (the lowest common multiple of the two denominators), convert each fraction to use that denominator, then add the numerators. So 1/4 + 2/3: the lowest common multiple of 4 and 3 is 12. 1/4 becomes 3/12, 2/3 becomes 8/12. Add the numerators: 3 + 8 = 11. The answer is 11/12. The calculator does all this for you and prints each step — useful for GCSE and KS3 revision when the working is what gets the marks, not just the answer.

Question 2

How do I multiply fractions?

Accepted Answer

Multiply the numerators together, then multiply the denominators together — no common denominator needed. So 2/3 × 3/5 = (2×3)/(3×5) = 6/15 = 2/5 after simplifying. The simplification is where most students lose marks: always reduce by dividing the top and bottom by their greatest common factor. The calculator shows both the unsimplified and simplified answer with the working — handy for checking your school homework.

Question 3

How do I divide fractions?

Accepted Answer

Flip the second fraction (find its reciprocal) and multiply. So 3/4 ÷ 2/5 becomes 3/4 × 5/2 = 15/8 = 1 7/8. The mnemonic UK GCSE teachers use is 'Keep, Change, Flip' — keep the first fraction, change ÷ to ×, flip the second. It works because dividing by a fraction is the same as multiplying by its reciprocal. Two negatives still cancel (if you've got minus signs), and the calculator handles improper-fraction-to-mixed-number conversion automatically.

Question 4

How do I convert a fraction to a decimal?

Accepted Answer

Divide the numerator by the denominator. So 3/4 = 3 ÷ 4 = 0.75, 1/8 = 0.125, 2/3 = 0.6666... (a recurring decimal). For GCSE and KS3, you're expected to know the common ones by heart: 1/2 = 0.5, 1/4 = 0.25, 3/4 = 0.75, 1/5 = 0.2, 1/8 = 0.125, 1/3 = 0.333. The calculator shows both the exact fraction and the decimal — use whichever form your question asks for.

Question 5

How do I simplify a fraction?

Accepted Answer

Find the greatest common factor (GCF or HCF) of the numerator and denominator, then divide both by it. So 12/18: factors of 12 are 1, 2, 3, 4, 6, 12 and factors of 18 are 1, 2, 3, 6, 9, 18 — the highest common factor is 6. Divide both by 6: 12÷6 = 2, 18÷6 = 3. So 12/18 simplifies to 2/3. The calculator does this automatically on every result. Worth practising the manual method for GCSE because exam papers want to see the working.

Question 6

What is an improper fraction?

Accepted Answer

An improper fraction has a numerator equal to or larger than its denominator — so 5/3, 7/4, 11/8 are all improper. The proper-fraction version would be a mixed number: 5/3 = 1 2/3, 7/4 = 1 3/4, 11/8 = 1 3/8. Both forms are mathematically correct. UK exam mark schemes usually accept either, but check the question — sometimes it specifies 'in its simplest form' or 'as a mixed number'. The calculator outputs both forms so you can match whatever the question wants.

Question 7

How do I add mixed numbers like 1 1/2 + 2 1/3?

Accepted Answer

Easiest method: convert to improper fractions first. 1 1/2 = 3/2, 2 1/3 = 7/3. Find a common denominator (6): 3/2 = 9/6, 7/3 = 14/6. Add: 9/6 + 14/6 = 23/6. Convert back to mixed: 23 ÷ 6 = 3 remainder 5, so the answer is 3 5/6. Enter the whole-number parts into the 'whole' boxes on the calculator and the rest fills in automatically — you don't have to do the improper-fraction conversion by hand.

Question 8

What does 2/3 + 3/5 equal?

Accepted Answer

2/3 + 3/5 = 19/15, which simplifies to 1 4/15 as a mixed number, or 1.267 as a decimal. The working: lowest common multiple of 3 and 5 is 15. 2/3 = 10/15, 3/5 = 9/15. 10/15 + 9/15 = 19/15. The 15 stays as the denominator because you're only adding numerators. 19 > 15 so it's improper, hence the conversion to 1 4/15. The calculator shows all these steps if you tick the 'show working' option.

Question 9

How do I convert 1 1/3 to a decimal?

Accepted Answer

Convert the fraction part to decimal first, then add the whole number. 1/3 = 0.3333... (recurring), so 1 1/3 = 1.333... For exam purposes, round to the required number of decimal places — usually 2 or 3. The standard GCSE rounding rules apply (look at the digit after the cut-off and round up if it's 5 or more). The calculator outputs both exact and rounded decimal forms, and shows when a decimal is recurring with the standard dot notation.

Question 10

Is this calculator allowed for GCSE maths exams?

Accepted Answer

For revision and homework, absolutely — it'll show full working which is what examiners reward. In an exam itself, you can't use any online tool, only an approved scientific calculator (Casio Classwiz fx-991EX, Casio fx-83GTX, or similar). What this tool is good for: checking your homework answers, working through past paper questions, and getting the step-by-step explanation when you're stuck on the method. We've designed it to match the way UK GCSE and KS3 textbooks lay out fraction working.

Question 11

What is 2 divided by 5?

Accepted Answer

2 ÷ 5 = 0.4. As a fraction, it's already 2/5 in simplest form. As a percentage, 0.4 × 100 = 40%. Common related results: 1 ÷ 5 = 0.2 (20%), 3 ÷ 5 = 0.6 (60%), 4 ÷ 5 = 0.8 (80%). Useful for converting test scores: 2 out of 5 correct = 40%.

Question 12

What is 100 divided by 14?

Accepted Answer

100 ÷ 14 = 7.142857... (recurring decimal). As a fraction: 100/14 simplifies to 50/7. As a mixed number: 7 and 2/7 (because 14 × 7 = 98, leaving remainder 2). Useful when dividing a total among 14 people or 14 groups — each share is exactly 50/7 or about 7.14.

Question 13

How do I convert a decimal to a fraction step by step?

Accepted Answer

Step 1: count decimal places. So 0.75 has 2 decimal places. Step 2: write it over the corresponding power of 10. 0.75 = 75/100. Step 3: simplify by finding the GCF. GCF of 75 and 100 is 25. So 75/100 = 3/4. For recurring decimals like 0.333..., use algebra: let x = 0.333..., then 10x = 3.333..., subtract: 9x = 3, so x = 3/9 = 1/3. Calculator does this automatically.

Question 14

What is 9 divided by 12 as a fraction?

Accepted Answer

9/12 simplifies to 3/4 (divide both by their GCF, 3). As a decimal: 0.75. As a percentage: 75%. This is the same as 9 ÷ 12 = 0.75. Common context: if you scored 9 out of 12 on a quiz, that's 75% — a B or B+ grade depending on the scale.

Question 15

What is 3/8 as a decimal?

Accepted Answer

3/8 = 0.375. Calculation: 3 ÷ 8 = 0.375 exactly (terminating decimal). As a percentage: 37.5%. Common eighths: 1/8 = 0.125 (12.5%), 2/8 = 0.25 (25%), 3/8 = 0.375 (37.5%), 4/8 = 0.5 (50%), 5/8 = 0.625 (62.5%), 6/8 = 0.75 (75%), 7/8 = 0.875 (87.5%). Eighths terminate cleanly because 8 is a power of 2.

Fraction Calculator — Add, Subtract, Multiply, Divide & Simplify

What this fraction calculator does

Fraction Operation Formulas

Example Calculation

Adding 2/3 + 3/4

Enter Fractions

When to Use This Calculator

Notes

Fraction to decimal & percent — every common fraction

Halves, thirds, quarters

Fifths

Sixths

Sevenths

Eighths

Ninths

Tenths

Twelfths

Sixteenths — imperial DIY

Twentieths and hundredths

Frequently Asked Questions

References

Inputs Explained

Limitations & Notes