math help

What is 30/50 + 7/9?

What is 30/50 + 7/9?

Here's how you add

30
50
+
7
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 30 by 9, and get 270, then we multiply 50 by 9 and get 450.

30/50 times 9

Do the same for the second term. We multiply 7 by 50, and get 350, then multiply 50 by 9 and get 450.

7/9 times 50

So now our fractions look like this:

270
450
+
350
450

Step 2

Since our denominators match, we can add the numerators.

270 + 350 = 620

So the answer is:

620
450

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:

620
450
÷ 2 =
310
225

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

Nope! So now we try the next greatest prime number, 5...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

310
225
÷ 5 =
62
45

Let's try dividing by that again...

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...

No good. 47 is larger than 45. So we're done reducing.

There you have it! Here's the final answer to 30/50 + 7/9

30
50
+
7
9
=
62
45
© 2014 Randy Tayler