math help

What is 45/3 + 1/7?

What is 45/3 + 1/7?

Here's how to add

45
3
+
1
7

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 45 by 7, and get 315, then we multiply 3 by 7 and get 21.

45/3 times 7

Do the same for the second term. We multiply 1 by 3, and get 3, then multiply 3 by 7 and get 21.

1/7 times 3

So now our fractions look like this:

315
21
+
3
21

Step 2

Since our denominators match, we can add the numerators.

315 + 3 = 318

So the answer is:

318
21

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...

No good. So next you try the next prime number, which is 3...

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

318
21
÷ 3 =
106
7

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 5...

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. 11 is larger than 7. So we're done reducing.

And we're done! Here's the final answer to 45/3 + 1/7

45
3
+
1
7
=
106
7
© 2014 Randy Tayler