Here's how you add
We have to make sure the denominators are equal.
Since 5 is evenly divided by 10, we can multiply just one term to get a common denominator.
Multiply 4 by 2, and get 8, then we multiply 5 by 2 and get 10.
The problem now has new fractions to add:
Since our denominators match, we can add the numerators.
8 + 7 = 15
This yields the answer
The last step is to reduce the fraction if we can.
To find out, we try dividing it by 2...
No good. So next you try the next prime number, which is 3...
No good. So next you try the next prime number, which is 5...
Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:
So far so good... let's try to divide by that number again.
No good. 5 is larger than 3. So we're done reducing.
And we're done! Here's the final answer to 4/5 + 7/10