What is 21/63 + 5/9?
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Here's how to add
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Step 1We have to make sure the denominators are equal. Since 9 is evenly divided by 63, we can multiply just one term to get a common denominator. Multiply 5 by 7, and get 35, then we multiply 9 by 7 and get 63. The problem now has new fractions to add:
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Step 2Since our denominators match, we can add the numerators. 21 + 35 = 56 This yields the answer
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Step 3The last step is to reduce the fraction if we can. To find out, we try dividing it by 2... No good. So next you try the next prime number, which is 3... No good. So next you try the next prime number, which is 5... No good. So next you try the next prime number, which is 7... Are both the numerator and the denominator evenly divisible by 7? Yes! So we reduce it:
So far so good... let's try to divide by that number again. No good. So next you try the next prime number, which is 11... No good. 11 is larger than 8. So we're done reducing. And we're done! Here's the final answer to 21/63 + 5/9
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