math help

What is 100/50 + 4/8?

What is 100/50 + 4/8?

Let's add

100
50
+
4
8

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 8, and get 800, then we multiply 50 by 8 and get 400.

100/50 times 8

Do the same for the second term. We multiply 4 by 50, and get 200, then multiply 50 by 8 and get 400.

4/8 times 50

The problem now has new fractions to add:

800
400
+
200
400

Step 2

Since our denominators match, we can add the numerators.

800 + 200 = 1000

This yields the answer

1000
400

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:

1000
400
÷ 2 =
500
200

Let's try dividing by that again...

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

500
200
÷ 2 =
250
100

Let's try dividing by that again...

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

250
100
÷ 2 =
125
50

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...

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

125
50
÷ 5 =
25
10

Let's try dividing by that again...

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

25
10
÷ 5 =
5
2

Let's try dividing by that again...

No good. 5 is larger than 2. So we're done reducing.

There you have it! Here's the final answer to 100/50 + 4/8

100
50
+
4
8
=
5
2
© 2014 Randy Tayler