Here's how to add


Step 1We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator. Now we multiply 1 by 9, and get 9, then we multiply 10 by 9 and get 90. Now for the second term. You multiply 1 by 10, and get 10, then multiply 10 by 9 and get 90. This gives us a new problem that looks like so:


Step 2Since our denominators match, we can add the numerators. 9 + 10 = 19 So what's the answer so far?


Step 3Can this fraction be reduced? First, we attempt to divide 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... No good. 23 is larger than 19. So we're done reducing. There you have it! Here's the final answer to 1/10 + 1/9
