math help

What is 4/40 + 5/9?

What is 4/40 + 5/9?

This is how you add

4
40
+
5
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 5 by 40, and get 200, then multiply 40 by 9 and get 360.

5/9 times 40

The problem now has new fractions to add:

36
360
+
200
360

Step 2

Since our denominators match, we can add the numerators.

36 + 200 = 236

This yields the answer

236
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:

236
360
÷ 2 =
118
180

Now, try the same number again.

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

118
180
÷ 2 =
59
90

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...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

Nope. Try the next prime number, 59...

Nope. Try the next prime number, 61...

No good. 61 is larger than 59. So we're done reducing.

Congratulations! Here's your final answer to 4/40 + 5/9

4
40
+
5
9
=
59
90
© 2014 Randy Tayler