What is the answer to 1/5 + 3/4

The answer is 19/20 & it doesn't simplify

In order to do this sum (without using a calculator) you must find the lowest common multiple of 5 and 4. It is 20. This means that the bottom part of both fractions must become 20. / 20 + / 20. For the top half, you must multiply the original top halves by what you multiplied the bottom halves. 1 X 4 = 4. 3 X 5 = 15. The question now becomes: 4/20 + 15 / 20. The answer is 19 / 20