What is 21/63 + 5/10?

Let's add

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 21 by 10, and get 210, then we multiply 63 by 10 and get 630.

Now for the second term. You multiply 5 by 63, and get 315, then multiply 63 by 10 and get 630.

We now have a new problem, that looks like this:

Step 2

Since our denominators match, we can add the numerators.

210 + 315 = 525

Answer:

Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide 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...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

Let's try dividing by that again...

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...

No good. 7 is larger than 5. So we're done reducing.

There you have it! Here's the final answer to 21/63 + 5/10