math help

What is 45/3 + 4/5?

What is 45/3 + 4/5?

Let's add

45
3
+
4
5

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 45 by 5, and get 225, then we multiply 3 by 5 and get 15.

45/3 times 5

Now for the second term. You multiply 4 by 3, and get 12, then multiply 3 by 5 and get 15.

4/5 times 3

This gives us a new problem that looks like so:

225
15
+
12
15

Step 2

Since our denominators match, we can add the numerators.

225 + 12 = 237

That gives us an answer of

237
15

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

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

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

237
15
÷ 3 =
79
5

Let's try dividing by that again...

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

Nope! So now we try the next greatest prime number, 7...

No good. 7 is larger than 5. So we're done reducing.

There you have it! Here's the final answer to 45/3 + 4/5

45
3
+
4
5
=
79
5
© 2014 Randy Tayler