Here's how to subtract 2/4 from 1/5:
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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 1 by 4, and get 4. Then we multiply 2 by 5, and get 10. Next we give both terms new denominators -- 5 × 4 = 20. So now our fractions look like this:
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Step 2Since our denominators match, we can subtract the numerators. 4 − 10 = -6 So the answer is:
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Step 3Last 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... Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:
Let's try dividing by 2 again... Nope! So now we try the next greatest prime number, 3... Nope! So now we try the next greatest prime number, 5... No good. 5 is larger than -3. So we're done reducing. There you have it! The final answer is:
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