math help

What is 7/9 + 4/10?

What is 7/9 + 4/10?

This is how you add

7
9
+
4
10

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 7 by 10, and get 70, then we multiply 9 by 10 and get 90.

7/9 times 10

Do the same for the second term. We multiply 4 by 9, and get 36, then multiply 9 by 10 and get 90.

4/10 times 9

The problem now has new fractions to add:

70
90
+
36
90

Step 2

Since our denominators match, we can add the numerators.

70 + 36 = 106

The sum we get is

106
90

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:

106
90
÷ 2 =
53
45

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...

Nope! So now we try the next greatest prime number, 29...

Nope! So now we try the next greatest prime number, 31...

Nope! So now we try the next greatest prime number, 37...

Nope! So now we try the next greatest prime number, 41...

Nope! So now we try the next greatest prime number, 43...

Nope! So now we try the next greatest prime number, 47...

No good. 47 is larger than 45. So we're done reducing.

There you have it! Here's the final answer to 7/9 + 4/10

7
9
+
4
10
=
53
45
© 2014 Randy Tayler