math help

What is 72/63 + 8/10?

What is 72/63 + 8/10?

This is how to add

72
63
+
8
10

Step 1

We 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 72 by 10, and get 720, then we multiply 63 by 10 and get 630.

72/63 times 10

Now for the second term. You multiply 8 by 63, and get 504, then multiply 63 by 10 and get 630.

8/10 times 63

This gives us a new problem that looks like so:

720
630
+
504
630

Step 2

Since our denominators match, we can add the numerators.

720 + 504 = 1224

That gives us an answer of

1224
630

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

1224
630
÷ 2 =
612
315

Let's try dividing by that again...

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:

612
315
÷ 3 =
204
105

Let's try dividing by that again...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

204
105
÷ 3 =
68
35

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...

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 35. So we're done reducing.

There you have it! Here's the final answer to 72/63 + 8/10

72
63
+
8
10
=
68
35
© 2014 Randy Tayler