math help

What is 80/2 + 2/10?

What is 80/2 + 2/10?

This is how we add

80
2
+
2
10

Step 1

Our denominators (bottom numbers) don't match, so we can't add yet.

Since 2 is evenly divided by 10, we can multiply just one term to get a common denominator.

Multiply 80 by 5, and get 400, then we multiply 2 by 5 and get 10.

80/2 times 5

The problem now has new fractions to add:

400
10
+
2
10

Step 2

Since our denominators match, we can add the numerators.

400 + 2 = 402

The sum we get is

402
10

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:

402
10
÷ 2 =
201
5

Now, try the same number again.

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

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

Nope. Try the next prime number, 7...

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

Congratulations! Here's your final answer to 80/2 + 2/10

80
2
+
2
10
=
201
5
© 2014 Randy Tayler