Here's how to subtract 4/9 from 2/5:
We can't subtract two fractions with different denominators. So you need to get a common denominator. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.
So we multiply 2 by 9, and get 18.
Then we multiply 4 by 5, and get 20.
Next we give both terms new denominators -- 5 × 9 = 45.
So now our fractions look like this:
Since our denominators match, we can subtract the numerators.
18 − 20 = -2
So the answer is:
Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?
To find out, we try dividing it by 2...
Nope! So now we try the next greatest prime number, 3...
No good. 3 is larger than -2. So we're done reducing.There you have it! The final answer is: