math help

What is 4/40 + 1/9?

What is 4/40 + 1/9?

Here's how you add

4
40
+
1
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 4 by 9, and get 36, then we multiply 40 by 9 and get 360.

4/40 times 9

Do the same for the second term. We multiply 1 by 40, and get 40, then multiply 40 by 9 and get 360.

1/9 times 40

The problem now has new fractions to add:

36
360
+
40
360

Step 2

Since our denominators match, we can add the numerators.

36 + 40 = 76

The sum we get is

76
360

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:

76
360
÷ 2 =
38
180

Let's try dividing by that again...

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

38
180
÷ 2 =
19
90

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 3...

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...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

No good. 23 is larger than 19. So we're done reducing.

There you have it! Here's the final answer to 4/40 + 1/9

4
40
+
1
9
=
19
90
© 2014 Randy Tayler