What is 21/63 + 7/11?
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Here's how we add
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Step 1Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator. Now you multiply 21 by 11, and get 231, then we multiply 63 by 11 and get 693. Do the same for the second term. We multiply 7 by 63, and get 441, then multiply 63 by 11 and get 693. The problem now has new fractions to add:
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Step 2Since our denominators match, we can add the numerators. 231 + 441 = 672 The sum we get is
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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... Nope! So now we try the next greatest prime number, 3... Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:
Let's try dividing by that again... Nope! So now we try the next greatest prime number, 5... Nope! So now we try the next greatest prime number, 7... Are both the numerator and the denominator evenly divisible by 7? Yes! So we reduce it:
Let's try dividing by that again... 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... No good. 37 is larger than 32. So we're done reducing. There you have it! Here's the final answer to 21/63 + 7/11
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