math help

What is 72/63 + 1/2?

What is 72/63 + 1/2?

Here's how you add

72
63
+
1
2

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 72 by 2, and get 144, then we multiply 63 by 2 and get 126.

72/63 times 2

Do the same for the second term. We multiply 1 by 63, and get 63, then multiply 63 by 2 and get 126.

1/2 times 63

The problem now has new fractions to add:

144
126
+
63
126

Step 2

Since our denominators match, we can add the numerators.

144 + 63 = 207

This yields the answer

207
126

Step 3

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

To find out, we try dividing 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:

207
126
÷ 3 =
69
42

Let's try dividing by that again...

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

69
42
÷ 3 =
23
14

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...

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 14. So we're done reducing.

There you have it! Here's the final answer to 72/63 + 1/2

72
63
+
1
2
=
23
14
© 2014 Randy Tayler