math help

What is 4/40 + 8/10?

What is 4/40 + 8/10?

This is how to add

4
40
+
8
10

Step 1

We have to make sure the denominators are equal.

Since 10 is evenly divided by 40, we can multiply just one term to get a common denominator.

Multiply 8 by 4, and get 32, then we multiply 10 by 4 and get 40.

8/10 times 4

The problem now has new fractions to add:

4
40
+
32
40

Step 2

Since our denominators match, we can add the numerators.

4 + 32 = 36

The sum we get is

36
40

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:

36
40
÷ 2 =
18
20

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

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

18
20
÷ 2 =
9
10

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 3...

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 9. So we're done reducing.

And we're done! Here's the final answer to 4/40 + 8/10

4
40
+
8
10
=
9
10
© 2014 Randy Tayler