Subtracting fractions with unlike denominators means finding the difference between two fractions that have different bottom numbers (denominators). To subtract them, you first need to make the denominators the same.
The denominator shows how many equal parts make up a whole. You can only subtract fractions when the parts are the same size.
To subtract fractions with different denominators, find a common denominator—usually the least common multiple (LCM) of the denominators. Then, make equivalent fractions that share that denominator.
Always make sure both fractions are written with the same denominator before subtracting. The numerator changes, but the denominator stays the same.
Once the fractions have the same denominator, subtract the numerators (top numbers) and keep the denominator the same.
Only subtract the numerators. The denominator tells how many total equal parts make up the whole and does not change.
When mixed numbers have unlike denominators, convert them into fractions with a common denominator before subtracting. You may need to regroup if the top fraction is smaller than the one you are subtracting.
If you cannot subtract because the top fraction is smaller, borrow 1 from the whole number and change it into a fraction with the same denominator before subtracting.
After subtracting, always check that your answer is in simplest form. Simplify the fraction if both numerator and denominator can be divided by the same number.
Fractions should always be written in simplest form unless the problem asks you to show all steps. Simplifying makes your final answer easier to understand.