math help

What is 78/10 + 2/7?

What is 78/10 + 2/7?

This is how to add

78
10
+
2
7

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 78 by 7, and get 546, then we multiply 10 by 7 and get 70.

78/10 times 7

Now for the second term. You multiply 2 by 10, and get 20, then multiply 10 by 7 and get 70.

2/7 times 10

This gives us a new problem that looks like so:

546
70
+
20
70

Step 2

Since our denominators match, we can add the numerators.

546 + 20 = 566

That gives us an answer of

566
70

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:

566
70
÷ 2 =
283
35

Now, try the same number again.

Nope. Try the next prime number, 3...

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

No good. 37 is larger than 35. So we're done reducing.

Congratulations! Here's your final answer to 78/10 + 2/7

78
10
+
2
7
=
283
35
© 2014 Randy Tayler