math help

What is 80/2 + 3/9?

What is 80/2 + 3/9?

This is how we add

80
2
+
3
9

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 80 by 9, and get 720, then we multiply 2 by 9 and get 18.

80/2 times 9

Do the same for the second term. We multiply 3 by 2, and get 6, then multiply 2 by 9 and get 18.

3/9 times 2

The problem now has new fractions to add:

720
18
+
6
18

Step 2

Since our denominators match, we can add the numerators.

720 + 6 = 726

The sum we get is

726
18

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:

726
18
÷ 2 =
363
9

Now, try the same number again.

Nope. Try the next prime number, 3...

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

363
9
÷ 3 =
121
3

Now, try the same number again.

Nope. Try the next prime number, 5...

No good. 5 is larger than 3. So we're done reducing.

Congratulations! Here's your final answer to 80/2 + 3/9

80
2
+
3
9
=
121
3
© 2014 Randy Tayler