What is 20/17 - 1/7?
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Here's how to subtract 1/7 from 20/17:
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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 20 by 7, and get 140. Then we multiply 1 by 17, and get 17. Next we give both terms new denominators -- 17 × 7 = 119. So now our fractions look like this:
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Step 2Since our denominators match, we can subtract the numerators. 140 − 17 = 123 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... Nope! So now we try the next greatest prime number, 3... Nope! So now we try the next greatest prime number, 5... Nope! So now we try the next greatest prime number, 7... Nope! So now we try the next greatest prime number, 11... Nope! So now we try the next greatest prime number, 13... Nope! So now we try the next greatest prime number, 17... Nope! So now we try the next greatest prime number, 19... Nope! So now we try the next greatest prime number, 23... Nope! So now we try the next greatest prime number, 29... Nope! So now we try the next greatest prime number, 31... Nope! So now we try the next greatest prime number, 37... Nope! So now we try the next greatest prime number, 41... Nope! So now we try the next greatest prime number, 43... Nope! So now we try the next greatest prime number, 47... Nope! So now we try the next greatest prime number, 53... Nope! So now we try the next greatest prime number, 59... Nope! So now we try the next greatest prime number, 61... Nope! So now we try the next greatest prime number, 67... Nope! So now we try the next greatest prime number, 71... Nope! So now we try the next greatest prime number, 73... Nope! So now we try the next greatest prime number, 79... Nope! So now we try the next greatest prime number, 83... Nope! So now we try the next greatest prime number, 89... Nope! So now we try the next greatest prime number, 97... Nope! So now we try the next greatest prime number, 101... Nope! So now we try the next greatest prime number, 103... Nope! So now we try the next greatest prime number, 107... Nope! So now we try the next greatest prime number, 109... Nope! So now we try the next greatest prime number, 113... Nope! So now we try the next greatest prime number, 127... No good. 127 is larger than 123. So we're done reducing. There you have it! The final answer is:
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