The denominators must be the same, the numerators can be different.
Adding and subtracting fractions can ONLY be done if the denominators are the same; then the calculation is done by adding or subtracting the numerators. Multiplying (and dividing) fractions does not require the denominators to be the same. To divide by a fraction the divisor is inverted (the original numerator becomes the new denominator and the original denominator becomes the new numerator) and then the fractions are multiplied. Multiplying fractions is achieved by multiplying the numerators together AND multiplying the denominators together. A whole number is the same as a fraction with the whole number as the numerator and a denominator of 1, so when multiplying by a whole number the denominator is multiplied by 1 (leaving it the same) and the is multiplication is effectively just multiplying the numerator by the whole number.
When simplifying fractions it's useful to know what is the HCF of the numerator and denominator is. When adding or subtracting fractions with different denominators it's useful to know what the LCM of them is.
first u find a common denominator
When adding or subtracting fractions first make sure that the denominators are the same if they aren't then find the lowest common denominator and alter the fractions accordingly
What is the definition of Adding and Subtracting Like Fractions
you subtract the numerator but the denominator stays the same.
numerator
Adding and subtracting fractions can ONLY be done if the denominators are the same; then the calculation is done by adding or subtracting the numerators. Multiplying (and dividing) fractions does not require the denominators to be the same. To divide by a fraction the divisor is inverted (the original numerator becomes the new denominator and the original denominator becomes the new numerator) and then the fractions are multiplied. Multiplying fractions is achieved by multiplying the numerators together AND multiplying the denominators together. A whole number is the same as a fraction with the whole number as the numerator and a denominator of 1, so when multiplying by a whole number the denominator is multiplied by 1 (leaving it the same) and the is multiplication is effectively just multiplying the numerator by the whole number.
A Common Denominator
You need a common denominator for both.
They have to have the same denominator.
No only when adding or subtracting fractions a common denominator is needed
When simplifying fractions it's useful to know what is the HCF of the numerator and denominator is. When adding or subtracting fractions with different denominators it's useful to know what the LCM of them is.
a common denominator
A common denominator is needed when adding or subtracting fractions of different denominators.
A common denominator.
Adding and subtracting fractions.