math help

What is 100/50 + 3/9?

What is 100/50 + 3/9?

Let's add

100
50
+
3
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 100 by 9, and get 900, then we multiply 50 by 9 and get 450.

100/50 times 9

Do the same for the second term. We multiply 3 by 50, and get 150, then multiply 50 by 9 and get 450.

3/9 times 50

The problem now has new fractions to add:

900
450
+
150
450

Step 2

Since our denominators match, we can add the numerators.

900 + 150 = 1050

This yields the answer

1050
450

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:

1050
450
÷ 2 =
525
225

Let's try dividing by that again...

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

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

525
225
÷ 3 =
175
75

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 5...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

175
75
÷ 5 =
35
15

Let's try dividing by that again...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

35
15
÷ 5 =
7
3

Let's try dividing by that again...

No good. 5 is larger than 3. So we're done reducing.

There you have it! Here's the final answer to 100/50 + 3/9

100
50
+
3
9
=
7
3
© 2014 Randy Tayler