math help

What is 72/63 + 7/11?

What is 72/63 + 7/11?

This is how to add

72
63
+
7
11

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 11, and get 792, then we multiply 63 by 11 and get 693.

72/63 times 11

Now for the second term. You multiply 7 by 63, and get 441, then multiply 63 by 11 and get 693.

7/11 times 63

This gives us a new problem that looks like so:

792
693
+
441
693

Step 2

Since our denominators match, we can add the numerators.

792 + 441 = 1233

That gives us an answer of

1233
693

Step 3

Can this fraction be reduced?

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:

1233
693
÷ 3 =
411
231

Let's try dividing by that again...

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

411
231
÷ 3 =
137
77

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...

Nope! So now we try the next greatest prime number, 41...

Nope! So now we try the next greatest prime number, 43...

Nope! So now we try the next greatest prime number, 47...

Nope! So now we try the next greatest prime number, 53...

Nope! So now we try the next greatest prime number, 59...

Nope! So now we try the next greatest prime number, 61...

Nope! So now we try the next greatest prime number, 67...

Nope! So now we try the next greatest prime number, 71...

Nope! So now we try the next greatest prime number, 73...

Nope! So now we try the next greatest prime number, 79...

No good. 79 is larger than 77. So we're done reducing.

There you have it! Here's the final answer to 72/63 + 7/11

72
63
+
7
11
=
137
77
© 2014 Randy Tayler