math help

What is 4/10 + 4/7?

What is 4/10 + 4/7?

Here's how we add

4
10
+
4
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 4 by 7, and get 28, then we multiply 10 by 7 and get 70.

4/10 times 7

Now for the second term. You multiply 4 by 10, and get 40, then multiply 10 by 7 and get 70.

4/7 times 10

This gives us a new problem that looks like so:

28
70
+
40
70

Step 2

Since our denominators match, we can add the numerators.

28 + 40 = 68

That gives us an answer of

68
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:

68
70
÷ 2 =
34
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 34. So we're done reducing.

Congratulations! Here's your final answer to 4/10 + 4/7

4
10
+
4
7
=
34
35
© 2014 Randy Tayler