math help

What is 20/17 + 3/5?

What is 20/17 + 3/5?

This is how we add

20
17
+
3
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 20 by 5, and get 100, then we multiply 17 by 5 and get 85.

20/17 times 5

Now for the second term. You multiply 3 by 17, and get 51, then multiply 17 by 5 and get 85.

3/5 times 17

This gives us a new problem that looks like so:

100
85
+
51
85

Step 2

Since our denominators match, we can add the numerators.

100 + 51 = 151

So what's the answer so far?

151
85

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...

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

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...

Nope! So now we try the next greatest prime number, 53...

Nope! So now we try the next greatest prime number, 59...

Nope! So now we try the next greatest prime number, 61...

Nope! So now we try the next greatest prime number, 67...

Nope! So now we try the next greatest prime number, 71...

Nope! So now we try the next greatest prime number, 73...

Nope! So now we try the next greatest prime number, 79...

Nope! So now we try the next greatest prime number, 83...

Nope! So now we try the next greatest prime number, 89...

No good. 89 is larger than 85. So we're done reducing.

There you have it! Here's the final answer to 20/17 + 3/5

20
17
+
3
5
=
151
85
© 2014 Randy Tayler