math help

What is 64/4 + 5/7?

What is 64/4 + 5/7?

This is how we add

64
4
+
5
7

Step 1

We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator - both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 64 by 7, and get 448, then we multiply 4 by 7 and get 28.

64/4 times 7

Do the same for the second term. We multiply 5 by 4, and get 20, then multiply 4 by 7 and get 28.

5/7 times 4

So now our fractions look like this:

448
28
+
20
28

Step 2

Since our denominators match, we can add the numerators.

448 + 20 = 468

So the answer is:

468
28

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

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

468
28
÷ 2 =
234
14

So far so good... let's try to divide by that number again.

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

234
14
÷ 2 =
117
7

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 3...

No good. So next you try the next prime number, which is 5...

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. 11 is larger than 7. So we're done reducing.

And we're done! Here's the final answer to 64/4 + 5/7

64
4
+
5
7
=
117
7
© 2014 Randy Tayler