math help

What is 30/50 + 2/8?

What is 30/50 + 2/8?

This is how to add

30
50
+
2
8

Step 1

Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator.

Now you multiply 30 by 8, and get 240, then we multiply 50 by 8 and get 400.

30/50 times 8

Do the same for the second term. We multiply 2 by 50, and get 100, then multiply 50 by 8 and get 400.

2/8 times 50

The problem now has new fractions to add:

240
400
+
100
400

Step 2

Since our denominators match, we can add the numerators.

240 + 100 = 340

This yields the answer

340
400

Step 3

The last step is to reduce the fraction if we can.

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:

340
400
÷ 2 =
170
200

Let's try dividing by that again...

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

170
200
÷ 2 =
85
100

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:

85
100
÷ 5 =
17
20

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...

No good. 19 is larger than 17. So we're done reducing.

There you have it! Here's the final answer to 30/50 + 2/8

30
50
+
2
8
=
17
20
© 2014 Randy Tayler