math help

What is 72/63 + 2/10?

What is 72/63 + 2/10?

Here's how to add

72
63
+
2
10

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 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 2 by 63, and get 126, then multiply 63 by 10 and get 630.

2/10 times 63

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

720
630
+
126
630

Step 2

Since our denominators match, we can add the numerators.

720 + 126 = 846

Answer:

846
630

Step 3

Now, do we need to simplify this fraction?

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

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

846
630
÷ 2 =
423
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:

423
315
÷ 3 =
141
105

Let's try dividing by that again...

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

141
105
÷ 3 =
47
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 + 2/10

72
63
+
2
10
=
47
35
© 2014 Randy Tayler