math help

What is 57/7 + 3/9?

What is 57/7 + 3/9?

This is how to add

57
7
+
3
9

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 57 by 9, and get 513, then we multiply 7 by 9 and get 63.

57/7 times 9

Do the same for the second term. We multiply 3 by 7, and get 21, then multiply 7 by 9 and get 63.

3/9 times 7

So now our fractions look like this:

513
63
+
21
63

Step 2

Since our denominators match, we can add the numerators.

513 + 21 = 534

Now we have an answer.

534
63

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...

Nope. Try the next prime number, 3...

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

534
63
÷ 3 =
178
21

Now, try the same number again.

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

No good. 23 is larger than 21. So we're done reducing.

Congratulations! Here's your final answer to 57/7 + 3/9

57
7
+
3
9
=
178
21
© 2014 Randy Tayler