math help

What is 7/20 + 6/12?

What is 7/20 + 6/12?

This is how we add

7
20
 +
6
12

Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 7 by 12, and get 84, then we multiply 20 by 12 and get 240.

7/20 times 12

Now for the second term. You multiply 6 by 20, and get 120, then multiply 20 by 12 and get 240.

6/12 times 20

This gives us a new problem that looks like so:

84
240
 +
120
240

Step 2

Since our denominators match, we can add the numerators.

84 + 120 = 204

So what's the answer so far?

204
240

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

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

204
240
 ÷ 2 =
102
120

Let's try dividing by that again...

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

102
120
 ÷ 2 =
51
60

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:

51
60
 ÷ 3 =
17
20

Let's try dividing by that again...

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...

No good. 19 is larger than 17. So we're done reducing.

There you have it! Here's the final answer to 7/20 + 6/12

7
20
 +
6
12
 =
17
20
© 2014 Randy Tayler

6/12 + 1/2
6/12 - 1/2
6/12 + 1/3
6/12 - 1/3
6/12 + 2/3
6/12 - 2/3
6/12 + 1/4
6/12 - 1/4
6/12 + 2/4
6/12 - 2/4
6/12 + 3/4
6/12 - 3/4
6/12 + 1/5
6/12 - 1/5
6/12 + 2/5
6/12 - 2/5
6/12 + 3/5
6/12 - 3/5
6/12 + 4/5
6/12 - 4/5
6/12 + 1/6
6/12 - 1/6
6/12 + 2/6
6/12 - 2/6
6/12 + 3/6
6/12 - 3/6
6/12 + 4/6
6/12 - 4/6
6/12 + 5/6
6/12 - 5/6
6/12 + 1/7
6/12 - 1/7
6/12 + 2/7
6/12 - 2/7
6/12 + 3/7
6/12 - 3/7
6/12 + 4/7
6/12 - 4/7
6/12 + 5/7
6/12 - 5/7
6/12 + 6/7
6/12 - 6/7
6/12 + 1/8
6/12 - 1/8
6/12 + 2/8
6/12 - 2/8
6/12 + 3/8
6/12 - 3/8
6/12 + 4/8
6/12 - 4/8
6/12 + 5/8
6/12 - 5/8
6/12 + 6/8
6/12 - 6/8
6/12 + 7/8
6/12 - 7/8
6/12 + 1/9
6/12 - 1/9
6/12 + 2/9
6/12 - 2/9
6/12 + 3/9
6/12 - 3/9
6/12 + 4/9
6/12 - 4/9
6/12 + 5/9
6/12 - 5/9
6/12 + 6/9
6/12 - 6/9
6/12 + 7/9
6/12 - 7/9
6/12 + 8/9
6/12 - 8/9
6/12 + 1/10
6/12 - 1/10
6/12 + 2/10
6/12 - 2/10
6/12 + 3/10
6/12 - 3/10
6/12 + 4/10
6/12 - 4/10
6/12 + 5/10
6/12 - 5/10
6/12 + 6/10
6/12 - 6/10
6/12 + 7/10
6/12 - 7/10
6/12 + 8/10
6/12 - 8/10
6/12 + 9/10
6/12 - 9/10
6/12 + 1/11
6/12 - 1/11
6/12 + 2/11
6/12 - 2/11
6/12 + 3/11
6/12 - 3/11
6/12 + 4/11
6/12 - 4/11
6/12 + 5/11
6/12 - 5/11
6/12 + 6/11
6/12 - 6/11
6/12 + 7/11
6/12 - 7/11
6/12 + 8/11
6/12 - 8/11
6/12 + 9/11
6/12 - 9/11
6/12 + 10/11
6/12 - 10/11
6/12 + 1/12
6/12 - 1/12
6/12 + 2/12
6/12 - 2/12
6/12 + 3/12
6/12 - 3/12
6/12 + 4/12
6/12 - 4/12
6/12 + 5/12
6/12 - 5/12
6/12 + 6/12
6/12 - 6/12
6/12 + 7/12
6/12 - 7/12
6/12 + 8/12
6/12 - 8/12
6/12 + 9/12
6/12 - 9/12
6/12 + 10/12
6/12 - 10/12
6/12 + 11/12
6/12 - 11/12