Here's how to subtract 2/5 from 4/10:


Step 1We 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 4 by 5, and get 20. Then we multiply 2 by 10, and get 20. Next we give both terms new denominators  10 × 5 = 50. So now our fractions look like this:


Step 2Since our denominators match, we can subtract the numerators. 20 − 20 = 0 So the answer is:


Zero divided by anything is just zero. So that's the final answer: 0 