math help

What is 70/99 - 4/5?

What is 70/99 - 4/5?

Here's how to subtract 4/5 from 70/99:

70
99
4
5

Step 1

We can't subtract two fractions with different denominators. So you need to get a common denominator. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator.

So we multiply 70 by 5, and get 350.

Then we multiply 4 by 99, and get 396.

Next we give both terms new denominators -- 99 × 5 = 495.

So now our fractions look like this:

350
495
396
495

Step 2

Since our denominators match, we can subtract the numerators.

350 − 396 = -46

So the answer is:

-46
495

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

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 -46. So we're done reducing.

There you have it! The final answer is:
70
99
4
5
=
46
495