math help

What is 25/15 + 4/10?

What is 25/15 + 4/10?

Here's how you add

25
15
+
4
10

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 25 by 10, and get 250, then we multiply 15 by 10 and get 150.

25/15 times 10

Do the same for the second term. We multiply 4 by 15, and get 60, then multiply 15 by 10 and get 150.

4/10 times 15

The problem now has new fractions to add:

250
150
+
60
150

Step 2

Since our denominators match, we can add the numerators.

250 + 60 = 310

The sum we get is

310
150

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:

310
150
÷ 2 =
155
75

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:

155
75
÷ 5 =
31
15

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...

No good. 17 is larger than 15. So we're done reducing.

There you have it! Here's the final answer to 25/15 + 4/10

25
15
+
4
10
=
31
15
© 2014 Randy Tayler